MSR SweetWater Microfilter Fast pumps water on both up and down strokes for a fast flow rate of 1.25 liters per minute Easy to use lever-action pump handle has a 4-to-1 mechanical advantage and dual pump action, so you don't have to work as hard Dependable eliminates over 99.9999 percent of all waterborne bacteria Simple to maintain simple brushing will restore a clogged filter Lifetime warranty And the pump lets you know when the filter needs replacing (each cartridge filters up to 200 gallons of water) 99.9 percent of common protozoan parasites, such as giardia and cryptosporidia