The Platypus DuoLock Soft Bottle is a soft bottle with a locking cap that’s designed to prevent leaks and lost caps. The DuoLock bottle also comes with a carabiner that you can hook around your finger, use as a pour handle, or attach to your backpack so it can’t pop out of a pocket accidentally. Like Platypus’ other soft bottles, the DuoLock bottles have a gusseted bottom so they stand up by themselves which is great when camping, they roll up small when empty and not needed, and impart no taste to your water.
I must admit, having a Platypus soft bottle cap that you can’t lose is really nice. I’ve been carrying a spare Platypus cap in my gear repair kit for the past five years. I once lost a cap on a very long backpacking trip and never wanted to experience that again!
Specs at a Glance
- Size: 1 liter, 0.75 liter
- Weight: 1 liter (1.6 oz), 0.75 liter (1.5 oz)
- Material: Nylon and Polyethylene (BPA-, BPS-, and phthalate-free)
- Dishwasher safe: top rack only
The DuoLock cap is connected to a pour spout by a plastic hinge, with a wire latch the snaps over the top of the cap to hold it closed securely so it can’t twist off or leak. You can also twist off the pour spout to give yourself a bigger opening, making it easier to clean or fill from natural water sources.
The bottle is made with a very durable, puncture-resistant plastic that’s BPA-, BPS-, and phthalate-free. You can freeze them, which is nice in summer, and they’re dishwasher safe (top rack only.) Platypus soft bottles are also tough and durable. You can roll them up thousands of times, scrape them up against rocks, and drop them without worrying about tearing or bursting one.
For backpacking use, the new Duolock bottles are not compatible with the most popular hollow fiber water filters or purifiers like the Katadyn BeFree, the Sawyer Squeeze, or the Sawyer Mini, because the cap is not threaded and is a different size. If you need a soft bottle that is compatible with the Sawyer filters, I’d recommend using Evernew soft bottles instead. You also need to be cautious with the security wire that locks the Duolock Cap closed because it can break, although Platypus does sell replacement DuoLock caps.
However, for more casual use when camping, day hiking, the gym, and especially for air travel, Platypus DuoLock Bottles let you enjoy the benefits of an ultralight, ultra-compact, reusable, roll-up soft bottle on the trail or closer to home.
Disclosure: Platypus provided me with this product, but I wasn’t under any obligation to review it.Editor's note: Help support this site by making your next gear purchase through one of the affiliate links above. Click a link, buy what you need, and the seller will contribute a portion of the purchase price to support SectionHiker's unsponsored and independent gear reviews, beginner FAQs, and free hiking guides.