Resolv Block Bait is built to last with a durable formulation labeled for indoor and outdoor use. Its active ingredient, bromadiolone, can deliver a lethal dose in one night’s feeding, with the first dead rodents appearing 4-5 days after feeding begins. Kills Norway rats, roof rats, house mice and warfarin-resistant Norway rats. Contains active ingredient bromadiolone, invented by the experts at Liphatech. Ideal for ongoing maintenance. Suitable for cleanouts. All-weather bait for wet or dry areas. 1 oz. mini block (16 lb. pail, approx. 250 mini blocks per pail). Vitamin K1 is the antidote.