The Katadyn MICROPUR MPI Purifier Tablets are a self-stable, easy-to-use water treatment option that purifies using chlorine dioxide. These tablets are effective against viruses, bacteria, giardia, and cryptosporidium, and are currently the only chemical treatment that doesn't require pre-filtering. The MicroPur MP1 tablets suit hikers, travelers, and campers wishing to avoid iodine treatments.