The Steripen Classic 3 with 40-micron pre-filter is the latest, most versatile model in our award winning Classic line. Winner of Time Magazine&&';;s Best Invention of 2001, it offers enhanced ergonomics and battery life as well as improved water resistance. An 8,000 treatment lamp delivers a lifetime of purification. Use four AA alkaline batteries to purify 50 liters of water or four lithium batteries to purify 150 liters. Includes a neoprene storage pouch. Batteries not included. Kit includes:Neoprene pouch, pre-filter. Details Effective against microorganisms product-description-viruses Suitable for groups up to 5 people Suitable for clear water only For daily or very frequent use Lightweight and portable for on-the-go adventures Specs Technology: uv Weight: (oz) 6 Battery type: 4 AA (not included) Number of liters per set of battery: 20/80-100/150 Number of liters per charge: Alkaline batteries: approx. 50 liters per set (depending on water quality). NiMH performance varies by mAh rating: 2300 provides about 100 liters. Lithium are the most economical choice. Lamp life: 8000 activations Volume options: 1 click = 0.5 liter, 2 clicks = 1 liter