Emergency Drinking Water Germicidal Tablets are intended for emergency disinfection of drinking water. When used as directed, they make most water bacteriologically suitable for drinking. Not to be used on a continuous basis. For short term or limited emergency use only. Treats up to 25 quarts.• Easy to use. No unpleasant taste• Iodine-based compound (no chlorine) Step 1: Add 2 tablets to 1 quart or liter of water and cap loosely to allow a small amount of leakage. Step 2: Wait 5 minutes. Step 3: Shake container to allow screw threads on the closure to be moistened, then tighten cap. Step 4: Wait 30 minutes before drinking. RECAP BOTTLE TIGHTLY. KEEP TABLETS DRY.Shelf life:Unopened - 4 years from manufacture date.Opened - 1 year from date of opening, or if they start to dis-color.