Harris Famous Roach & Silverfish Killer Tablets 6 oz. uses a boric acid formula with added lure to kill roaches water bugs & silverfish. One box can treat an entire house making it one of the most efficient and cost-effective ways to kill a roach. Tablets contain a lure that draws roaches near to feed. Just place tablets in out of the way areas where roaches travel and roaches will find them. Once ingested roaches die within days. For use indoors in homes apartments hotels restaurants boats RVs garages attics and other locations where cockroaches are found. Always follow label directions and keep out of reach of children.