Contrac Blox 4x 4lbs Active Ingredient: Bromadiolone Rodents can consume a lethal dose in just one feeding Each bait blox weighs approximately one ounce. Highly palatable, yet weatherable, bait that works well in wet and dry conditions. RATS: Place 3 to 16 CONTRAC BLOX (usually at intervals of 15 to 30 feet) per placement. Maintain an uninterrupted supply of fresh bait for at least 10 days or until signs of rat activity cease. MICE: Place 1 block per placement. Space placements at 8- to 12- foot intervals. Two CONTRAC BLOX may be needed at points of very high mouse activity. Maintain an uninterrupted supply of fresh bait for at least 15 days or until signs of mouse activity cease. Packaging: 4x 4 lbs