Contains ol’ tried and true iodine, but doesn’t taste horrible. The initial chemical reaction makes water smell a little funky at first, but dissipates slowly over time. Effective against bacteria, viruses and cysts, such as Giardia Lamblia. Treats up to 25 quarts of water (requires 2 tabs per quart) and requires a 30-minute treatment time. Meets EPA standards. 50 tablets.