A Thermacell Fuel Cartridge Refills - 4 Pack provides up to a total of 48 hours of relief when used with Thermacell devices and Thermacell Repellent Mats. The Fuel Cartridges heat and activate the mosquito repellant in these mats, which repel mosquitos by creating a 15-foot zone of protection. From the backyard to the great outdoors, keep your Thermacell devices fueled to rebuff tiny biting fiends with a Thermacell Fuel Cartridge Refills - 4 Pack. Fuel-only refill, repellent mats not included For use in fuel-powered Thermacell repellers, lanterns, and torches Can be stored for long periods of time Package contains: 4 fuel cartridges each lasting 12 hour Manufacturer's one-year limited warranty