RODENT CONTROL - Revenge Rodent Smoke Bombs are effective on gophers, moles, woodchucks, Norway rats, skunks, and ground squirrels. NO SECONDARY POISONING - These smoke bombs eliminate secondary poisoning concerns. Use with caution and follow the directions on the package. HOW IT WORKS - Once activated, the smoke bomb emits a thick, dense, suffocating, and toxic smoke into rodent burrows. The smoke bomb traps the rodents in their burrow. Be sure that all other exits of the burrow are blocked and secured. HOW MANY TO USE - One cartridge per burrow should be adequate and work well in most cases. Larger rodents like the groundhog may require more than one, but it is not recommended to use more than two smoke bombs. WARNING OF FIRE HAZARD - Do not use this product under a porch, shed, or indoors. It is a possible fire hazard, and it can be toxic to people and animals if not used properly.