Katadyn's lightweight Vario Dual Technology MicroFilter adjusts for dirty water or normal water conditions, so you get the cleanest, freshest water possible no matter where you're backpacking. A simple turn engages the ceramic prefilter when you're pumping out of a muddy lake so the pleated glass-fiber filter inside doesn't get destroyed. After a long, hard hike, this Katadyn water filter's dual piston pump works smoothly and easily--pumping out up to 2-liters per minute. The Vario Dual Technology Filter removes waterborne bacteria so you can drink safely on your camping trips, and uses a replaceable carbon core and cleanable ceramic disc. Attach Katadyn's adaptor base directly to your standard Nalgene water bottle opening, or use the output hose for larger water containers.