Gravityworks System 4lFiltering up to 1. 75 liters a minute without any pumping, the high capacity GravityWorks Water Filter System filter is one of the easiest and fastest ways to get filtered water in the backcountry. With two different sizes 6. 0L & 4. 0L the GravityWorks is ideal for bigger backpacking groups or basecamps. Offering an 8 or 12 liter total capacity, either model easily supplies filtered water for drinking, washing up, cooking, and cleaning. Simplify your