Steripen Adventurer Opti Water Purifier

Features: 
Easy to use: Simply click the button to activate, place in water and stir; when water is purified, the UV lamp turns off and an indicator signals
Ultraviolet UV-C light rays safely sterilize clear water by destroying 99.99% of protozoa, including giardia, cryptosporidia, bacteria and even viruses
UV-C purification of clear water helps protect you from risks that cause botulism, cholera, dysentery, typhoid and more
Optical sensor doubles as a convenient LED flashlight
Retail package includes 2 non-rechargeable (disposable) CR123 batteries, a neoprene case with belt loop, and user instructions
Device works with containers with minimum 1.75 in. diameter opening (i.e. Nalgene wide-mouth bottles)
One set of CR123 batteries will treat up to 50 liters of water
UV lamp life: 8,000 treatments
Small and lightweight, weighing just 3.8 oz. with batteries
Recipient of Backpacker Magazine's 2011 Editors' Choice Award