The Thermacell Mosquito Repellet system effectively repels mosquitoes, black flies, and other biting insects by creating a 15 x 15-foot zone of protection for bug-free comfort. Ideal for use while you are camping, hunting, fishing, gardening, and around the backyard, Thermacell products have been evaluated by the EPA for safety and effectiveness. Each Original mat provides up to 4 hours of repellency Refills work with all Thermacell repeller devices (Repellers, Lanterns, and Torches) Refill pack includes 3 repellent mats and 1 butane cartridge for 12 hours of repellency