Kills mosquitoes before they’re old enough to bite. The mosquito dunks are America's best selling home owner mosquito control product. The only product with bit, a bacteria toxic only to mosquito larvae, that lasts 30 days and treats 100 square feet of surface water. Non-toxic to all other wildlife, pets, fish and humansSimply apply Mosquito Dunks to any standing water or water gardenKills within hours lasts for 30 days or moreHighly effective low impact product