Adventurer Opti system uses UV light rays instead of chemicals to purify water for drinking. Ultraviolet (UV-C) light rays safely sterilize clear water by destroying 99.99% of protozoa (including Giardia and Cryptosporidia ), bacteria and even viruses.
Simple to use: just press a button and gently agitate the water with a quick stir. Purifies 16 fl. oz. of water (cold or warm) in less than a minute, or 32 fl. oz. in a minute and a half

The Adventurer Opti package includes 2 non-rechargeable (disposable) CR123 batteries and a neoprene case with belt loop. SteriPEN does not recommend the use of alkaline batteries, as they provide very few treatments. Device works with containers with minimum 1.75 in. diameter opening (ie Nalgene wide-mouth bottles).