Original Thermacell Mosquito Repellent Refills effectively repel mosquitoes by creating a scent-free 15 ft zone of protection when used in fuel-powered Thermacell Repellers. Ideal for use while you are camping, hunting, fishing, gardening and around the backyard. 48 hours of mosquito protection refills, for use in fuel powered Thermacell Repellers, Lanterns and Torches. Each repellent mat lasts up to 4 hours and each fuel cartridge lasts up to 12 hours. No spray and no mess. Scent and DEET-free. Active ingredient is Allethrin, a synthetic version of a naturally occurring repellent found in chrysanthemum flowers. Includes 12 repellent mats and 4 fuel cartridges.