Compact handheld UV water purifier designed specifically for emergencies * Destroys more than 99.9 percent of harmful microorganisms, including Giardia * Safe and effective without altering taste, pH, or other properties of water * Purifies 200 half-liter servings of water per 4 AA lithium batteries (not included) * Measures 1.5 x 7.6 x 1.5 inches (W x H x D); weighs 5.7 ounces