The SteriPen Classic 3 Water Purifier is the original handheld UV water purifier. Reliable and portable,it's capable of treating 50 L of water using alkaline batteries and a staggering 150 L using lithium ion batteries. . Destroys over 99.9% of water borne microorganisms that cause illness with UV light. Treats up to 50 L with alkaline batteries or 150 L using lithium ion batteries. Accepts alkaline, lithium ion, and NiMH batteries. LED indicator panel lets you know treatment size and status of batteries and UV lamp. Bulb will treat up to 8000 L of water. Super easy to use: Just activate, place in water, and stir LED indicators flash to let you know when water is safe to drink.