The only EPA-Registered Purification Tablets on the market. Effective against Cryptosporidium, Giardia, bacteria, and viruses. 20 tablets per pack. Unlike iodine tablets that have a strong chemical taste and murky orange-yellow color, these Katadyn Micropur Purification Tablets leave you with only the taste of fresh water. These tablets are easy to use and have the same proven technology used in municipal water supplies. They are lightweight and compact, making them ideal for traveling, backpacking, and emergency use. 20-pack.