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Platypus DuoLock SoftBottle Review

The DuoLock is an updated version of the SoftBottle that has a new lid, making it easier to drink from.
Top Pick Award
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Price:  $14 List | Check Price at Amazon
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Pros:  Useful carabiner attachment, well-designed lid, lightweight, very collapsible
Cons:  Tips easily, hard to clean
Manufacturer:   Platypus
By Jane Jackson ⋅ Senior Review Editor  ⋅  May 8, 2018
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#17 of 19
  • Ease of Use - 35% 6
  • Durability - 20% 4
  • Ease of Cleaning - 20% 4
  • Weight - 15% 10
  • Taste - 10% 5

Our Verdict

We have explored many iterations of the collapsible bottle over the years. We have found that it is surprisingly hard to make a new, yet still effective, bottle that is lightweight and compact. Well, it seems that Platypus has done just that with the Platypus DuoLock SoftBottle. This bottle is super lightweight, easy to carry, and has a revolutionary lid design that changed our opinion on collapsible bottles in general. The Duolock also has a carabiner attachment point that we found to be very useful for climbing, as it can be attached to your harness. There are many pros to this new design from Platypus, and we are happy to give the bottle the Top Pick for Collapsible Award this year.

Pro tip — On extended backcountry trips, we like coupling the DuoLock with a Nalgene.

Compare to Similar Products

Our Analysis and Test Results

Much like its predecessor, the Platypus SoftBottle, the DuoLock is light, portable, and ideal for hiking in the backcountry or climbing up a multi-pitch route. The bottle is easy to fill, and the new lid makes it easy to drink from. The downsides to this bottle are also similar to the SoftBottle. It is difficult to drink from at times since its flexible body is a bit floppy. Also, the bottle is one of the more difficult ones to clean since its mouth is narrow and due to some nooks and crannies that are hard to reach.

Performance Comparison

This bottle is best used on hikes or stuffed into a climbing pack because of its weight and portability.
This bottle is best used on hikes or stuffed into a climbing pack because of its weight and portability.

Ease of Use

The DuoLock has a collapsible plastic body and screw-on cap. What sets the DuoLock apart from previous Platypus models is its newly designed lid, which has two parts. The lid can be removed for easy filling, but it also has a flip cap that makes for easy drinking. We found that we spilled water on ourselves a lot less. Some bottles have similar lid designs, but the DuoLock's actually makes sense with the overall design of the bottle. Another plus for this contender is that it forms to the space available in your pack for easy stowing. The flexible body is also helpful when filling the bottle in shallow streams in the backcountry. It is leak-proof beyond any doubt, and easily rolls up and fits into your pocket when empty.

On the downside, drinking from this collapsible bottle requires a learned skill, and usually requires two hands. Its soft flexibility makes it flop around when trying to grab a drink, which will lead to spills if you're not careful. This is not a one-handed drinking bottle, but if you're using this bottle, hopefully, you are in the backcountry or on some kind of adventure where you will have time to use both hands to hydrate yourself! The DuoLock also had a tendency to fall over, which is a problem for all lightweight, collapsible bottles we have tested.

When full  the Platypus DuoLock stands up on its own  even on uneven surfaces!
When full, the Platypus DuoLock stands up on its own, even on uneven surfaces!

This contender also has one of the smallest mouths of all bottles we tested, making it hard to fill up from faucets with large or powerful water streams. As we mentioned with the Platypus SoftBottle, the DuoLock has a small mouth that will require a different bottle for purification with some filters or a Steri-Pen. This is a reminder for those who are planning on taking this bottle into the backcountry. Liquid and tablet water treatments will work fine in this bottle, though, as would a Sawyer Mini water filter.

The DuoLock combines a secure lid with a useful and effective spout  making it our new favorite over the older  simpler Platypus SoftBottle.
The DuoLock combines a secure lid with a useful and effective spout, making it our new favorite over the older, simpler Platypus SoftBottle.


The DuoLock can easily handle drops and falls onto hard surfaces. It breezed through our drop tests, barely suffering a scratch (a minute scratch on the cap was all). That said, you can't expect a collapsible bottle to last forever. It held up fine in our three-month review, but in personal experience, we haven't had a collapsible bottle that held up much more than a year. For this reason, we recommend always having another water container as a backup. If you fold the bottle up for storage frequently, the bottle will wear more quickly along the fold lines and could risk having a hole form on the seam.

The DuoLock gets its name from this lid design. Instead of screwing the lid down  it locks into place  eliminating leakage.
The DuoLock gets its name from this lid design. Instead of screwing the lid down, it locks into place, eliminating leakage.

Ease of Cleaning

We must admit, the DuoLock bottle is not easy to clean. You'll need a specialized, thin brush if you want to really get in there. Without such a brush, it took us about 5 minutes to clean this bottle. Other bottles, with wide mouths (Nalgene, Yeti, Lifefactory) were much easier to clean, but none are as portable as the DuoLock. That being said, you probably won't be filling this bottle up with coffee or flavorful teas, and a light rinse is enough to get it clean in the backcountry, so it cleans well enough for the settings and uses it is most comfortable in.


The DuoLock is one of the lightest bottles in this review, weighing in at 1.6 ounces. That works out to being only five-hundredths of an ounce per fluid ounce. That means that the weight in your pack is not your bottle, but just the water you need to keep going on the trail. The other collapsible bottles scored right in line with the DuoLock in this metric.

It is in this category that the bottle really shines. Lightweight, rigid bottle options are the Nalgene Wide-Mouth or the CamelBak Eddy+, both of which weight in at around 6 oz, making them light, but still nearly 5 oz heavier than the DuoLock.

Here  the compact size of the DuoLock is shown on the left  while the Platypus Meta on the right does not collapse nearly as well.
Here, the compact size of the DuoLock is shown on the left, while the Platypus Meta on the right does not collapse nearly as well.


Drinking from this water bottle tasted fine at first. However, if you store your water in this bottle for over 24 hours, expect it to have a plastic-y taste. It also retained the taste of the flavored sports drink in subsequent fills. Much like the LifeStraw Go, we recommend filling the PlatyPus DuoLock with water only. This is the downside of the bottle being plastic, and collapsible as the flexible plastic seems to impart its flavor on the liquid more than solid plastic bottles, like the Thermos Intak, CamelBak Eddy, and LifeStraw bottles.

Unfortunately, the DuoLock ran into the same issues that the SoftBottle did in terms of soapy flavor retention. After an issue with lingering soapy flavor, we were able to return the bottle to a neutral taste after filling it with baking soda and vinegar for 12 hours and rinsing. The best way to use these malleable plastic bottles is to simply use them for drinking water and try not to get other flavors imparted into their plastic walls. For a bottle that does not retain taste, we recommend checking out the Yeti Rambler or another stainless-steel option or a glass bottle, like the LifeFactory model.

The carabiner on the DuoLock is substantial enough to clip onto a harness when rock climbing.
The carabiner on the DuoLock is substantial enough to clip onto a harness when rock climbing.

Best Applications

The DuoLock will serve you best in the backcountry. It stows neatly, it's very light, and can handle rugged treatment. This product makes a great backup reservoir and even better primary vessel when equipped with an auxiliary drinking tube. You can even fold it up and fit it in your back pocket, making it the most portable bottle we tested. The carabiner clip is useful for attaching to your harness, and we found this bottle to be the best option for an on-route bottle out there. It can also be attached to a backpack if you like hanging your water on the outside of your pack.


At $14, the DuoLock is a bottle of value for those of us who frequently go on multi-day trips. It is packable and light, and easy to fill from streams. The value of this bottle significantly drops when using it in the office as your primary bottle, which we think is a terrible idea. It doesn't stand up well on its own, much like the Soma Bottle, one of our glass contenders. The Platypus SoftBottle is $5 cheaper, but we really liked the lid design of the DuoLock and felt like it was worth the extra bucks. Other inexpensive options include the Nalgene and the Thermos Intak 24.


The Platypus DuoLock is an ideal bottle for backpacking and traveling. Its lightweight design, clever lid, and incorporated carabiner clip make this bottle a great option for those counting ounces for their next adventure. The flexible body can collapse into the size of a plastic bag and stows away easily. It is easy to fill this bottle from a stream, but the narrow mouth makes it hard to filter water. It also requires two hands for drinking, which means it is not the ideal bottle for road trips. Overall, the DuoLock is a great bottle and our Top Pick for collapsible bottles.

Jane Jackson