This is one of the lighter hydration reservoirs that we've tested. It does this by having a very simple opening with not a lot of plastic. The downside to this approach is that this is not the easiest reservoir to fill or clean. But if you avoid sports drinks and really like to go light then this may be a great option for you. Otherwise we would advise you to check out the Platypus Big Zip SL which has a large opening that is easy to fill and clean. We also recommend you look at the CamelBak Crux Reservoir which won our Best Buy award and the Geigerrig Hydration Engine which won our Editors' Choice award.
Platypus Hoser Review
Compare prices at 2 resellers Pros: Light weight, good value, lifetime warranty
Cons: Difficult to clean, difficult to drink from bite valve, not the easiest to fill
Our Analysis and Test Results
In some ways this is an old-school style hydration bladder because it has such a simple opening. In other ways it is an advanced water bottle with a drinking tube. We find it comes down to two factors: are you really concerned with going lightweight and do you mainly just drink water without adding sugary sports drink powders.
Ease of Filling
This is one of the more difficult bladders to fill because the opening is so small. Also, because you remove the entire tube before filling you then need a place to put it. This is not a big deal if you are filling it in your house but it is a bigger deal when in slightly gross campground bathrooms.
We did not encounter any durability issues and expect this to have above average long-term performance. It is backed up by a lifetime guarantee.
There is no lock off mechanism on the drinking tube and bites valve. This was the only hydration bladder without that function. This means you have to be extra careful when throwing the bladder and bites valve in the back of your car or in a backpack. Furthermore, the connection of the two does not use a quick release so you can easily swap out this drinking tube with another brand such as the Camelbak (you can do this with the platypus big zip SL which uses a quick release for the drinking tube).
Ease of Drinking
Like its sibling the Platypus Big Zip SL, we did not find it particularly easy to drink from this bite valve. It is still passable, however we expect more after using the CamelBak, Geigerrig, and Osprey models where the water shoots out.
Ease of Cleaning
Because of the tiny opening it is difficult to get a brush inside the bladder to clean it. Therefore we don't recommend this bladder if you often use sports drinks as it will be difficult to keep clean.
Are you someone who is obsessed with moving light and fast? Are you a big fan of the other platypus bottles? If so, this may be ideal for you. However, if you are a mountain biker or day hiker used to the ease of filling and ease of cleaning up other hydration bladders, this might not be the best option. Another consideration for people wanting to move light in the backcountry or climbing is the MSR DromLite.
— Chris McNamara