Easy to use blocks control all species of pocket gophers. Moisture resistant and remains palatable to gophers for extended period of time in the burrow. "Two block" application system leaves adequate bait in the burrow to control gophers invading the burrow after the death of the original gopher. The blocks are designed specifically for subterranean use around homes only. Contains 4 blocks per package. Active ingredient: Diphacinone.