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. This bottle is best used in backcountry settings - you can even fold it up and fit it in your back pocket, making it the most portable bottle we tested. The carabiner clip-in point adds to its versatility in the wilderness.
Platypus DuoLock SoftBottle Review
Compare prices at 3 resellers Pros: Useful carabiner attachment, well-designed lid, lightweight, very collapsible
Cons: Tips easily, hard to clean
Manufacturer: Platypus
Our Verdict
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Platypus DuoLock SoftBottle | |||||
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| Awards |  |  | | | |
| Price | Check Price at REI Compare at 3 sellers | $8.73 at REI Compare at 2 sellers | $18.99 at Amazon | $10 List | $10.46 at Backcountry Compare at 2 sellers |
Overall Score  |
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| Star Rating | |||||
| Pros | Useful carabiner attachment, well-designed lid, lightweight, very collapsible | Light, durable, resists flavors, simple design, wide mouth makes for easy filling | Affordable, insulates well, has interchangeable lids, portable | Inexpensive, passed our drop tests, easy to carry, easy to drink from, ergonomic design | Lightweight, portable, updated straw is an improvement |
| Cons | Tips easily, hard to clean | Diameter too big for cup holders, wide mouth makes it difficult to drink from when walking or driving | Paint chipping after a few months of use, flip cap seemed to lack security | Narrow mouth makes it hard to clean by hand, heavy, inherently less durable than steel competition | Straw and bite valve still attract mold and dirt, flavors linger |
| Bottom Line | This bottle combines a collapsible design with a spout for convenient, easy drinking | A tried and tested classic, this model is versatile and reasonably priced | This is one of our top ranking bottles because it's easy to use, just the right size, lightweight and inexpensive | This affordable bottle's no-nonsense, ergonomic design wins us over for the top glass option of all we tested | For those who like a built-in straw design, this bottle has survived the test of time as a proven model |
| Rating Categories | Platypus DuoLock So... | Nalgene Wide-Mouth | Simple Modern Summit | Ello Pure 20 | Camelbak Eddy+ |
| Ease Of Use (40%) | |||||
| Durability (25%) | |||||
| Weight (20%) | |||||
| Taste (15%) | |||||
| Specs | Platypus DuoLock So... | Nalgene Wide-Mouth | Simple Modern Summit | Ello Pure 20 | Camelbak Eddy+ |
| Body Material | Nylon/ Polyetholyene | Eastman Tritan co-polyester | 18/8 stainless steel | Glass/ BPA-free silicone | BPA-Free Polypropylene |
| Empty weight (oz) | 1.6 oz | 6.4 oz | 12.4 oz | 18.5 oz | 7.1 oz |
| Volume (oz) | 34 oz | 34 oz | 22 oz | 20 oz | 25 oz |
| Bottle weight (oz) per fluid oz capacity | 0.05 oz | 0.19 oz | 0.56 oz | 0.93 oz | 0.28 oz |
| Mouth diameter | .75 in | 2.5 in | 2.25 in | 1.75 in | 2.25 in |
| Base diameter | 6 in | 3.25 in | 3 in | 3 in | 3 in |
| Height | 11 in | 8.25 in | 9.5 in | 10.75 in | 9.25 in |
| Body Type | Collapsible | Hard-sided/traditional | Hard-sided/traditional | Hard-sided/traditional | Hard-sided/traditional |
| Free of Materials | BPA-free | BPA, BPS and Phthalate Free | BPA-free | BPA-free | BPA, BPS, BPF |
| Cap/Lid Type | Duo-Lock flip cap | Loop-top screw cap | Screw Cap | Screwtop | Screw cap with straw |
| Volume Options | .75 L, 1L | 16 oz, 48 oz | 14 oz, 18 oz, 22 oz, 32 oz, 40 oz | 20 oz | .6 L, .75 L, 1 L |
| Warranty | Limited Warranty | Lifetime Guarantee for normal use | Limited Warranty | Lifetime warranty | Got Your Bak Lifetime Guarantee |
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
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.
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. Its narrow mouth also makes it quite challenging to clean. 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.
Durability
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.
Weight
It is in this category that the bottle really shines.
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.
Taste
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.
Unfortunately, the DuoLock had some issues with 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.
Value
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.
Conclusion
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