In an emergency, you need something that's dependable and fool-proof. Katadyn® Emergency Drinking Water Tablets are specially formulated to disinfect water when other methods are not possible. Each tablet disinfects 1 liter (about 1 quart) of water for drinking or cooking. Effective against viruses, bacteria, Giardia and Cryptosporidium. Also removes bad tastes and odors. Simply add tablet to a quart of water and let sit away from sunlight for four hours. Trusted by campers and hikers, militaries and emergency organizations. Meets EPA microbiological water purifier test standards. Each package contains 30 tablets (enough to purify 30 liters of water).