Contrac Cake is a single feeding bait that kills rats and mice within days. The active ingredient, Bromadiolone, produces mortality in a single feeding, even in anticougulant-resistant rodents. Contrac Cake is weather proof and holds up well in high-moisture environments without becoming rancid. Only the highest quality food-grade ingredients are used to ensure the highest acceptability by rats and mice. Contrac Cake comes in 1 lb. multi-edged, scored cakes that can be broken into 4 oz., 2 oz. or 1 oz. blocks for rat and mice placements. Each box comes with 16 - 1 lb. cakes.