The Platypus GravityWorks Pump-Free Water Filtration System delivers fast, pump-free performance with even less weight and more ease. Using advanced, Hollow Fiber technology and a little physics, the Platypus GravityWorks allows you to collect, transport, filter and dispense water, easier and faster than any other system available. Delivering four liters of filtered water is just 2.5 minutes with no pumping, there's simply no easier or faster way to get safe water away from home. Ideal for bigger groups, the system's eight-liter capacity eliminates both the worry and hassle of keeping plenty of water around for anything you need.
I used this on a recent backpacking trip in Rocky Mountain National Park. For this trip the performance was flawless. There were five people in our group and the gravity works 4 liter easily suppled all the water we needed for drinking and cooking. However there was one issue that can slow down the water filtered. When filling the the dirty bag (water to be filtered) it is extremely easy to fill in a fast moving stream or small waterfall. The problem occurred when filling the dirty bag in a very small pool of water. Water pressure can collapse the bag making it difficult to fill. If there is enough room to scoop water this is no problem. Water filters quickly into the clean bag once the filter is back flushed removing air bubbles. Based on the number of water reservoirs I had to fill and the amount of meals prepared, the Platypus gravity works system was money well spent, allowing me to handle other camp chores instead of constantly pumping water. Highly recommend this Platypus product.