Sawyer SP160 - One Gallon Gravity Water Filtration SystemA lightweight, robust solution for filtering large quantities of water in as little as 7 minutes, Sawyers 1 Gallon Gravity System with dual threaded MINI filter is ideal for backpacking, backcountry camping, and emergency preparedness. With threads on both sides, you can screw the push pull cap onto the MINI for easy on off functionality while filtering to control water flow. Our lightest and most versatile personal water filtration system, the Sawyer