Hands-free output, no pumping required! Take this simple gravity microfilter system on your next overnighter. Makes even bacterially contaminated water safe to drink, without changing its mineral content. A pleated glass-fiber filter element removes bacteria, protozoa and cysts from drinking water, including Salmonella, Colibacillosis, Vibrio cholera, Amoeba, Schistosoma (Bilharziasis), Giardia, Cryptosporidium, etc.