A Time Magazine Invention of the Year winner, LifeStraw contains no chemicals, no batteries and no moving parts to wear out. It features a high flow rate and weighs only 2oz. It is perfect for the Ultralight backpacker, camper, hiker, traveler, boy scout, hunter or for emergencies. Unlike many similar filters on the market today, LifeStraw has met EPA standards for water filtration in independent testing. LifeStraw has been used around the world under extreme conditions for humanitarian relief. Does not filter chemicals, salt, viruses, heavy metals, taste. Shelf life has been extended to 5 years. Please NOTE: It takes roughly 3-5 seconds of sucking to start the flow of water through the filter.