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