Thermacell&nbsp;R-3 Mosquito Repeller Refill,&nbsp;36 Hour&nbsp;Pack (9 Repellent Mats and 3 Fuel Cartridges) Refill pack includes 36 hours of mosquito protection refills Each repellent mat lasts up to 4 hours and each fuel cartridge lasts up to 12 hours For use in Thermacell Repellers, Lanterns, and Torches. Turn it on Mosquitoes Gone! Scent-free and DEET-free 15-foot mosquito protection zone Active ingredient is Allethrin, a synthetic version of a naturally occurring repellent found in chrysanthemum flowers 100% Satisfaction Guarantee on all Thermacell products Package contains: 36 hours of refills - 9 repellent mats and 3 fuel cartridges