Mosquito Control Rings, set of 20

Any standing water can breed swarms of mosquitoes, even your birdbath or rain barrel. Our Mosquito Controls contain Bt 'Israelenis, ' a naturally occurring bacterium that kills mosquito larvae for a full 30 days. Each slow-release, floating Control Ring treats 100 square feet of surface area in your pond or water garden. Control mosquitoes naturally Rings last for a month Each ring treats 100 square feet Rings measure 2-1/4" diameter by 3/4" thick Each ring, placed in water, controls 100 square feet of water surface area, no matter how deep. Can be stored in a dry, cool area for up to two years.