When heated in any ThermaCELL appliance, the ThermaCELL Mosquito Repellent Refill effectively repels mosquitoes, black flies, no-see ums and sand flies with a scent that lingers continuously for up to four hours per mat. The repellent, allethrin, is a synthetic analog (chemical copy) of a naturally occurring insecticide, pyrethrin, found in the pyrethrum flower, a member of the chrysanthemum family.

Includes: (1) Butane cartridge, (3) Repellent mats Each cartridge lasts up to 12 hours, and each mat lasts up to 4 hours.

Make sure your ThermaCELL Mosquito Repellent keeps protecting you from those biting insects. Don't run out of refills!