Micropur MP1 tablets release chlorine dioxide, the same substance used in municipal drinking water plants worldwide. So not only is the water safe to drink, it also tastes great. Tablets are individually sealed for longest shelf life (5 years). Each of the 30 tablets included treats 1 liter of water. Wait time is as follows: 15 minutes for Viruses and Bacteria in all water, 30 minutes for Crypto and Giardia in normal water (60ºF, clear water), and 4 hours for Crypto in worst case water (39º F, very dirty, slightly acidic water, i. e. the kind you'd want to double pump with a purifier).