to top 10 table

10 Best Soft Flasks Tested

last updated Oct 07, 2018
Hydration is an important factor when it comes to running. If you are not properly hydrated you will become fatigued, overheated, overworked, and will not be able to perform properly.

Keeping a soft flask with you can help eliminate the possibility of becoming dehydrated because it allows you to comfortably and efficiently carry your water with you. Some water bottles can be heavy and bulky, but soft flasks and collapsible bottles allow you to carry your water or electrolyte drink without having to deal with those factors.

Soft flasks are a lightweight and comfortable alternative to the traditional water bottles, however, it is important to know what your most high quality and durable options are.

We have taken the liberty of testing a variety of soft flasks out, to find the best of the best of 2018. Below you will find the best 2018 has to offer, so scroll below to find out which one is the best option for you!
Researched Sources
11
Researched Sources
Reviews Considered
1.1k
Reviews Considered
Hours Researching
17
Hours Researching
Products Evaluated
10
Products Evaluated
Last Updated:
Avatar
By Mark Smith:

This update brings you fresh content on Best Soft Flasks 2018. We also added newly asked questions to our FAQ-section. Still questions unanswered? That's what we're here for, So please ask away! 10/7/18 This article has been remade in the brand new format to make it easier for our readers to find exactly what they need.

Sorting Options
Size Water Resistance Durability By Default
Rank
PictureProduct
Name
Rating
Shops
1
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
96.7
Size
95%
Water Resistance
98%
Durability
97%
Price Comparison Last Updated (17.11.18)
$14.90
2
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
95.3
Size
97%
Water Resistance
95%
Durability
94%
Price Comparison Last Updated (17.11.18)
3
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
94.7
Size
95%
Water Resistance
93%
Durability
96%
Price Comparison Last Updated (17.11.18)
$23.95
4
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
94
Size
95%
Water Resistance
92%
Durability
95%
Price Comparison Last Updated (17.11.18)
5
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93.7
Size
94%
Water Resistance
93%
Durability
94%
Price Comparison Last Updated (17.11.18)
$22.49
6
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93.3
Size
94%
Water Resistance
92%
Durability
94%
Price Comparison Last Updated (17.11.18)
$26.99
7
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93
Size
93%
Water Resistance
93%
Durability
93%
Price Comparison Last Updated (17.11.18)
8
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
91.7
Size
94%
Water Resistance
92%
Durability
89%
Price Comparison Last Updated (17.11.18)
$44.46
9
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
91.3
Size
86%
Water Resistance
92%
Durability
96%
Price Comparison Last Updated (17.11.18)
$12.48
10
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
88
Size
86%
Water Resistance
88%
Durability
90%
Price Comparison Last Updated (17.11.18)
$16.74
In Depth Review Top 10
  • SLS3
  • ITYYT
  • Nomader
  • Raidlight EazyFlask
  • Ultimate Direction Bottle with Kicker Valve
  • Aonijie
  • Hydrapak SF500 SoftFlask
  • Katadyn BeFree Water Filtration System
  • Hydrapak Softflask Hydration Flask
  • Salomon
Table of contents
  • Criteria Used for Evaluation
  • Other Factors to Consider
  • Frequently Asked Questions
  • Sources

10 Best Soft Flasks

1. SLS3

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
96.7
SLS3
Size
95
Water Resistance
98
Durability
97
best offer for today
$14.90
Pros:
  • Leak proof
  • Very lightweight
Cons:
  • Top is hard to open and close, so not good for races.

The SLS3 Soft Flask is extremely lightweight, adding minimal bulk to your running gear. The bite valve makes it easy to use while in motion, whether you are running, hiking, or training at the gym.

Read more

Volume
This flask holds 17 ounces. It holds cold liquids only.

Construction
This bottle is made of collapsible BPA-free material. Even with welded seams, it weighs only 28 grams. The bite valve helps keep air out, preventing the water from sloshing around inside the bottle while you run, eliminating the potential for distractions or gait disruptions.

Durability
Although this bottle is highly durable and leak proof, users report that it may be too much so. The leak-proof cap is reported to be very difficult to open and close, so users recommend using a different bottle while racing. However, users also note that it is a great choice for people that throw their water bottle into their bag or purse, because it definintely won't leak!

Value
This is a slightly below average priced soft flask.

2. ITYYT

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
95.3
ITYYT
Size
97
Water Resistance
95
Durability
94
best offer for today
Pros:
  • Hot and cold beverages
  • Wide mouth for ice
Cons:
  • Questionable durability of security strap

Available in 4 colors, this soft flask is built with a wide mouth so you can put ice inside for extra cool refreshments.

Read more

Volume
This bottle holds 26 ounces. It can hold cold beverages with ice, or it can hold moderately warm drinks, up to 100 degrees.

Construction
FDA approved, BPA-free medical grade silicone was used to construct the ITYYT Collapsible Water Bottle. It can withstand temperatures from -40 to 100 degrees, holding both cold and hot beverages. It is also capable of accommodating ice cubes for those runners that enjoy a freezing cold drink during their workout. After rolling up, this soft flask can be held securely with a strap.

Durability
Silicone is highly durable, and can withstand being dropped on a run, thrown into your bag, or a cycle through the dishwasher. The lid seal and valve are leakproof, and the cap keeps out dust and debris. Some users report that the closure strap fell off after a few uses.

Value
This is an inexpensive soft flask.

3. Nomader

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
94.7
Nomader
Size
95
Water Resistance
93
Durability
96
best offer for today
$23.95
Pros:
  • Durable, non-toxic, and eco-friendly construction
  • Holds cold and hot beverages
Cons:
  • Must “pre-condition” the bottle for proper water taste

Nomader products were inspired by, you guessed it, nomads. Their gear, like the Collapsible Water Bottle, was designed for people with on-the-go, active lifestyles that are outdoors or travel frequently. This durable soft flask stores conveniently making staying hydrated on a long run a breeze.

Read more

Volume
The Nomader Collapsible Water Bottle holds 22 ounces of water or another liquid. It can hold both hot and cold beverages.

Construction
The silicone construction of this soft flask is free of BPA, lead, PVC, phthalates, and other chemicals. It can hold hot or cold drinks, and rolls up securely with an attached belt-style strap. This soft flask is available in 9 colors to match every taste, wardrobe, or set of travel gear.

Durability
The silicone construction of this soft flask is made to withstand wear and tear, and can hold up to temperatures as low as -4 degrees Fahrenheit and as high as 248 degrees Fahrenheit. It is equipped with a removable heat protection sleeve. It is shatterproof and is safe for the dishwasher and freezer. The cap is leak proof because of its “twist and lock” design, and has an anti-germ spout cover.

Value
This is an averaged priced soft flask.

4. Raidlight EazyFlask

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
94
Raidlight EazyFlask
Size
95
Water Resistance
92
Durability
95
best offer for today
Pros:
  • Durable
  • Low price
  • Comes with removable straw and nozzle 
  • Lightweight
Cons:
  • Some users don’t like the straw option

While Raidlight is not as a popular brand here in the United States, it is highly popular in Europe. This flask comes from a French company known for their hydration flasks and it is available in 150mL, 350mL, and 600mL.

Read more

Volume
This soft flask comes in 3 different volume options: 150mL, 350Ml, and 600mL.

Construction
This bottle is made is BPA free and also comes with an expandable drinking straw, so you don't have to take your bottle out while on your run. If you don't like the straw, it also comes with a removable nozzle.

Durability
This flask is highly durable and able to withstand a lot.

Value
This bottle is highly affordable, with variable prices depending on which size you get.

5. Ultimate Direction Bottle with Kicker Valve

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93.7
Ultimate Direction Bottle with Kicker Valve
Size
94
Water Resistance
93
Durability
94
best offer for today
$22.49
Pros:
  • TPU construction
  • Diswasher safe
Cons:
  • Small fill head

This TPU collapsible soft flask conforms to any shape and keeps you hydrated on the go. The bite valve makes it a good choice for both regular workouts and races.

Read more

Volume
This soft flask holds 14 ounces. It is suitable for cold liquids only.

Construction
This soft flask is made of TPU. It is clear so you can easily see how much liquid is left in the bottle, keeping you aware of when it is time to fill up. The nozzle is a high flow bite valve, so getting a swig of water on your run is quick and easy. This feature is especially convenient while racing. Users noted that the fill head is very small, making filling this flask a difficult, messy task.

Durability
TPU is a highly durable material and is dishwasher safe.

Value:
This is an average priced soft flask.

6. Aonijie

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93.3
Aonijie
Size
94
Water Resistance
92
Durability
94
best offer for today
$26.99
Pros:

It’s very lightweight

It’s very easy to carry even in a run belt

Great price

Cons:

Some runners complained about unpleasant aftertaste

Aonijie may be not the most popular brand when it comes to making soft flasks but their products are very high quality. This product is also 100% BPA free.

Read more

Volume
There are two sizes available- you can choose 250 ml pack or 500 ml pack.

Construction
This flask is collapsible so if you don’t need to use it, you can easily roll it and carry in your pocket. It was constructed to prevent any kind of leaking. This one can be frozen- you can leave it for a night and the next day, you will get very fresh, cooled down taste. You don’t need to squeeze it a lot to get your water. When you drink, this soft flask shrinks so the more your drink, the lighter it is. There’s wide mouth design which is great for runners. It’s constructed with TPU.

Durability
It is well-made, the firm construction provides the long lifetime of the product.

Value
The pricing here is very reasonable and you can save some money with this one. Great price for good quality product.

7. Hydrapak SF500 SoftFlask

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93
Hydrapak SF500 SoftFlask
Size
93
Water Resistance
93
Durability
93
best offer for today
Pros:

It was awarded with ISPO award

Runners said that materials feel very durable

There’s possibility to put smaller ice cubes inside

Cons:

Some runners complained that it doesn’t have a strap to attach to the clothes

This soft flask is a big hit amongst runners- it can be filled both with water and gel. Like many other products on our list, it’s BPA free. Have a look at the newest version of this soft flask!

Read more

Volume
There are two different sizes that you can choose from- 250 ml and 500 ml.

Construction
This Hydrapak SoftFlask was made with TPU. This material makes this product much more durable and it also provides a lot of flexibility. The top can be easily removed which makes cleaning much more easier. It is very easy to carry as there’s special finger loop and you can store it without problems. You get a lot of fluid when you squeeze even a little bit.

Durability
The TPU construction and welded seams make this bottle extremely durable against wear and tear and leaks.

Value
Some of you may think that this is a real bargain but you must be aware that the size isn’t also big so we could say it’s an average price.

8. Katadyn BeFree Water Filtration System

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
91.7
Katadyn BeFree Water Filtration System
Size
94
Water Resistance
92
Durability
89
best offer for today
$44.46
Pros:
  • Water filtration system
  • Easy to clean
Cons:
  • High price
  • Filter is fragile.

The Katadyn BeFree is a unique soft flask because it has a built in water filtration system so you can rehydrate anywhere your run takes you. Replacement filters are available to keep you using this flask for a long time.

Read more

Volume
The Katadyn BeFree Water Filtration System holds 20 ounces of water. Water is the only liquid that should be used it this flask.

Construction
This collapsible soft flask is equipped with a .1 micron water filter, which can remove potential harms from your drinking water, including Giardia and Cryptosporidium . It has an EZ-Clean Membrane which tidies up with just a slosh of water.

Durability
The flask portion of this bottle is highly durable, but users have some reservations about the filter. The advise being extra gentle with it, as the small components can be damaged really easily. Replacement filters are available for purchase from Katadyn.

Value
This is a high priced soft flask. The high price is a result of the filtration system that is built into the bottle.

9. Hydrapak Softflask Hydration Flask

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
91.3
Hydrapak Softflask Hydration Flask
Size
86
Water Resistance
92
Durability
96
best offer for today
$12.48
Pros:
  • Inexpensive
  • Lightweight
  • Can also hold energy gels 
  • Fits in most vests, belts or back pockets
  • BPA and PVC free
Cons:
  • Only holds 250mL (approximately 8 ounces)

The Hydrapak Softflask Hydration Flask is a small and lightweight option for runners. It comfortably and easily can fit in a pocket or vest without adding weight that will hold you back during your runs.

Read more

Volume
This flask can hold 250mL of water or your electrolyte drink as well as 8 servings of energy gels.

Construction
This is a TPU, HDPE, and Silicone soft flask. It is BPA and PVC free as well as dishwasher safe.

Durability
Highly durable and easy to carry. Not easily breakable.

Value
Highly affordable.

10. Salomon

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
88
Salomon
Size
86
Water Resistance
88
Durability
90
best offer for today
$16.74
Pros:
  • TPU construction
  • Very small when collapsed
Cons:
  • May leak
  • Funny smell
  • No strap or hook

This soft flask compresses as you drink from it, instantly lessening the bulk to carry while you run. It is also one of the smallest flasks once fully compressed and folded.

Read more

Volume
This flask holds 8 ounces of liquid. It is only suitable for cold liquids.

Construction
The Salomon Soft Flask is made of PVC-Free TPU. It can be folded small enough to fit in the palm of your hand, but has no closing strap or fastener to attach it to your outfit. Users report this bottle has an odd smell that never goes away. As a result, some users purchased a replacement flask after just a short time.

Durability
TPU is an extremely durable material, so this soft flask can stand up to bumps and drops. Some users report leakage after only a short period of use.

Value
This is an average priced soft flask.

Criteria Used for Evaluation

Size

There is a wide range of sizes available on the market.

On the market, there’s a wide range of soft flasks products. They can be used by everybody but when it comes to runners, the size or the volume is really crucial. While taking part in a race you can’t stop to drink some water. This is why soft flasks were invented. You should personalize your product. There is a wide range of sizes available on the market. Bigger ones are best for those who are very thirsty during a race or a contest and they don't have a problem with taking something bigger. Those runners who aren't very interested in carrying soft flasks who are bigger than usual should choose the normal or a small version. The big problem that many runners encounter is that the producer offers only one size. This is a big inconvenience as it may small for well-built men and he would have to take 2 or 3 packages to slake his thirst. On the other side, runners who need only a few of this product, they may be discouraged by the fact that this is an additional burden during the race. When it comes to choosing the shape, we don't have a wide range of shapes. This is because the best shape that you can carry during the race is similar to a rectangle. However, you can always check the measurements of the product. Producers very often give the details about the width and length.  You may think that this is something that you shouldn't care about, usually soft flasks really fit you. However, you should check the measurements for one reason. If you want to carry your soft flask in your pocket, you must be aware that sometimes the product is too big. We would recommend checking the measurements of the pocket and of the product and it will give you more confidence. The volume is the very individual case. If you want to carry your soft flask with you, we would recommend purchasing 0.6 liters. It will make you feel hydrated and you won't carry too heavy. On the market, there are also available soft flask with 2 liters and it's perfect for cooling down after the race.

Water Resistance

Sometimes, you unintentionally squeeze the product too much and the gel or water starts to leak. This is because the cap isn't strong enough...

The big problem when purchasing a soft flask is finding the product which won’t be leaking. Even the most durable material or cap may not be enough. Even the best companies offer the products that may have a problem with leaking. Sometimes, you unintentionally squeeze the product too much and the gel or water starts to leak. This is because the cap isn't strong enough to stay in place. However, buying a product which is harder to open isn’t the best idea. During the race, you may have problems with hydration as the snap lid may be very hard to open. Leaking of the product is a very common problem among the runners. The leakage of the water is not a very pleasant thing as you have all your suit wet, especially the trousers and it doesn't look good. Although the leakage of the water is really annoying, the leakage of the gel or any other substance is worse. This is because they have a different consistency and your whole pocket start to be sticky. What's more, the smell of the gel may be really terrible for some runners and that's why a solid package is needed. This is why many runners decide to purchase their product in a local store or that want to at least see the product and touch it. The best option is to check if the product is leakage-free and then you can purchase it online. Check if the cap is well made, it can't be a cheap, plastic one. You can even try to squeeze the product to see whether the problem happens. Remember that if you close the product not good enough, it is obvious that it will leak so it's not always the matter of the quality of the product.

Durability

A good test of the durability of the product is to check if after 2 or 3 usages it smells okay.

Good durability is a key to success. Always check how the product was made and don’t search for products with lower class materials only because they’re cheaper. They are probable to last fewer months than those with normal prices.  A good test of the durability of the product is to check if after 2 or 3 usages it smells okay. If the products smell bad, it's obvious that this soft flask was made with very cheap material and we wouldn't recommend to use it anymore. Low-quality products aren't durable but many readers can't even check the durability because they throw them away much earlier. Why? Because some soft flasks, these poorly made, may change the taste of the water. This is something that is the most disgusting thing. Would you like to drink water with some chemicals in it? Checking if there is not any leakage while using the product is the best test for durability. As we've said before, it sometimes runner's fault because he or she won't close the cap good enough and there's a leakage. If you see that you have a leaking soft flask, you may be sure that your product won't be durable. Durability should be an important factor, you spend money on the product- you want the best quality. What you must remember is that you can't keep your one soft flask for years. After this time, your product won't be able to perform some functions that are essential to good hydration.

Other Factors to Consider

Features

Beyond being used as a package for liquid substance, you should consider the other aspects of soft flasks. Let’s start with cleaning. Many buyers who buy this kind of product often complain about cleaning the product. It’s true because it’s not easy to clean and not every product can be washed in a dishwasher. Cleaning is an important part as it makes your device bacterial free. You should clean your device at least once a week or even more, it depends how much do you use it. It’s also a good idea to check if you can attach the product to your clothes. It may really make it easier to carry it, rather than wearing it in a pocket. It's very uneasy, especially during the race or marathon, to check your pockets for the soft flask. It's better to have it attached and you can run, observe the track and drink at the same time. Remember also that you need to read carefully the description of the product because not every package can be used with both liquid and gels. Sometimes you can pull the water only. This is is something that annoys many runners when they can't pull the liquid inside the tube. And if you want to fill the soft flask, you need to also make sure that it’s suitable for both hot and cold beverages. Pulling the hot water into the tube may really destroy it and we don't really recommend to take hot water with you for a marathon or race. It will get much hotter and you won't be able to drink it.

Value

Here comes the last factor to evaluate but of course not less important. As we said before, it’s not worth to search for really cheap products as they are likely to leak and they’re not very durable. They also can have an impact on water taste and smell. From the other side, the best products aren’t always the most expensive ones. You should really carefully check the price as there are other volumes. This is a common mistake that people buy a product that is cheaper but they forget to check the volume. We have got on our list the product from less than 10 dollars to up to 30. This is because we want to present the products that are available not only for rich people or very professional runners. We want to provide products for those who can't spend too much on this kind of staff but they still want to enjoy good quality. people often compare the prices in stores to those in online shops. The differences aren't big and you must remember that you must also pay for a delivery when you shop online. When it comes to soft flasks, we would really recommend investing your money. Most of these products are reusable and you can enjoy them for a very long time. It's a total must-have for marathon runners. We know that they are given the water during the race, but your own soft flask is a perfect idea as you can fill it with energizing gel and boost your performance. It's better to pay a bit higher price and enjoy the best quality.

Flexibility

This is something that may be the most useful additional convenience. The filter is a great way to protect your health. Filters are built in a soft flask to clear the water. It doesn't let bacteria to get in. This convenience is adored by the runners who take part in mountain races. They can take the water from the lake. The filter will clear the water so you will be able to drink it with no worries about bacteria. Producers are aware that this option is very useful and attracts many clients. This is why there are many products on the market and also on our list that has the filter. Above the filter, the second most demanded thing that runners really adore is easy rolling up the tube. When you use the product, there is less and less gel, it's similar to ending of the toothpaste. This is why it's easy to roll the tube - it is smaller and you have less problem with drinking. You would think that's not an important thing but when you take part in the contest, you will know how crucial it is. During the race, it should be easy to roll the tube and drink. We're talking about this because there are some products when the tube can be rolled. It's very stiff and it's really uncomfortable and it may have a bad impact on your running performance.

Style

We always must to talk about it because we really read all the users comments and this is why this factor is here. When running started to be not only a sport but some kind way of life, many people started to really look for stylish devices for the running sessions. This isn't a secret that you want to look good in your outfit with your running soft flask. This boosts your confidence and it gives you more power to overcome the obstacles. People really started to pay attention to details and the result is a wide range of soft flask to choose from. Producers happen to know that the nicer the product is, the biggest change is for the customer to buy it. We have soft flasks in many different colors. Flashy ones are the most popular, some even have reflective logos to be more visible for the others. We have different designs, there is a big variety of drawings that can be put on the soft flask in order to make us look different. This is very useful if we want to leave our product for a moment. If our product is different from the other, it's less probable that someone will by mistake take our soft flask.

Weight

This is the factor that we at first didn't intend to put on our list. while reading the reviews, we came to the conclusion, that for some runners this may be very important. The weight of the product may be a big thing for people who carry their soft flask in the pocket. You know the feeling when your pockets are full and you can't even move freely because of there to much stuff in your pockets. A soft flask, even if it's small, it may weight a lot. this may be a really uncomfortable experience as you have additional burden to carry. this may have an impact on your performance as one of your legs has a harder task. Of course, we're not talking about something very heavy, but when you need to fight the wind resistance, even this little device may really make it harder for you to run faster.

Brand

If you shop online, you must be aware that the product may be destroyed during the delivery- it's very rare but it happens. This is why you should check if the product is okay in the presence of the delivery agent. The soft flask is this kind of stuff that you must really check. This is because in many cases there's nothing like money back and etc. If during the making flask in the factory, something went wrong, you have a law to give back the product and to demand the new one. The hardest thing here is to prove that it is a factory fault not yours that the product is not complete or doesn't work. The one thing that every customer hate is filling all the documents about the product if they want the money back or want a new product. This is why we recommend to really read carefully all our factors as to prevent from purchasing the product that will let you down.

Frequently Asked Questions

q: Why should I use these soft flasks?
a:

Good question. Imagine that you’re taking part in a race. After a few miles, you start to be thirsty, you need water or you won’t be able to finish the race. However, you can’t take a big bottle of water with you because it would have a really bad impact on your performance. What do you do? You take a soft flask, you can carry it in your pocket or you can usually attach it to your clothes. You are usually able to carry not only water but also other fluids, gels, and other liquid substances. This boost of energy and hydration will let you improve your performance and you will feel better after it. What we must underline is that the soft flask isn't only for runners. they can be used by everyone. This is a good idea if you don't want to carry the bottle with water. This solution is often chosen by people who love hiking in the mountains. During their excursion, they can take the water from the river or stream (of course if the soft flask has a filter).

q: My soft flask started to smell bad. What can I do?
a:

If your product isn’t old you should try to use some kind of antibacterial cleaner. The smell should disappear. If your soft flask starts to smell bad after not many usages, it may mean that it's low-quality product.

q: What is BPA?
a:

BPA is a chemical that can be used to make many types of plastic. Some researches proved that it can get into the food or water and it may have a bad impact on the brain and the other parts of the human body. That’s why a lot of products on our list is BPA-free.

If you are in need of packable hydration on the go, a soft flask may be an option for you. They are light, stowable, and easy to fill and clean. Use this review of the Best Soft Flasks to help choose the bottle that will keep you running for miles and miles.

q: Could you make a comparison on soft flasks vs bottles?
a:

There are some runners that prefer to use soft flasks, other think the bottles are better. It really depends on your personal opinion. Soft flasks are usually adored by those who don’t like to carry heavy bottles of water. The construction of the soft flask is very lightweight and the shape is much different. Some people say that the bottles restrict the movement too much and that’s why they prefer the second option. When it comes to leaking, it also really depends on the brand. While taking part in a marathon, it’s very important to have easy access to water and the flow must be also appropriate. People who don’t like soft flasks, they complain about the small amount of water- it’s true that usually, bottles have more liters but it really depends. All in all, soft flasks will be great for those who don’t need such big amount of water and they don’t want to carry heavy bottles that could have a bad effect on their speed and running performance.

Sources