Don't risk getting sick! Field-tested SteriPEN Handheld Water Purifier makes drinking water safe, pure. Lightning fast! In about 48 seconds it purifies 16 fl. ozs. at the touch of a button. Compact SteriPEN creates powerful ultraviolet light that destroys the DNA of microbes in seconds, so they can't reproduce and make you sick. Uses the same smart technology used by U.S. spring water boiling plants and state municipal plants to purify water. A powerful, germicidal UV lamp comes on automatically when immersed in a glass of water. Adjustable to fit domestic and international water bottles (a smart precaution). More: Destroys cryptosporidium, giardia lamblia salmonella, E-coli, dysentery, cholera, hepatitis, influenza, plus dozens more waterborne bacteria, viruses and protozoa; Depending on battery life, output can yield 30-180 liters (8 3/4-147 1/2 gal.) of pure water; UV lamp lasts approx. 5,000 applications; Uses 4 AA batteries (not included); 7" long, and 7 ozs., easily fits pocket, pack or purse. TIP: always drink upstream from the herd. And trust SteriPEN for pure water when hiking, military field maneuvers and international travel. Order up for H2O protection! SteriPEN Water Purifier