All the gear and plans in the world are no good if your water supply is contaminated. Keep your water clean and drinkable with the CamelBak All Clear Microbiological UV Water Purifier. Capable of treating nearly a liter of water at a time, the All Clear runs an 60 second cycle time during which ultraviolet light inactivates viruses, bacteria, and cysts. An intuitive LED display keeps you informed as to when you're OK to hydrate. The included set of CR123 batteries will treat 0. 7 liters of water, keeping you hydrated for the duration of even multi day expeditions.