Thermacell Max Life refills offer up to 12 uninterrupted hours of mosquito repellency. The Thermacell Mosquito Repeller 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.