Thermacell Mosquito Repellent Refill - As thousands of repeat customers will tell you, Thermacell is unbeatable at repelling mosquitoes, black flies, and no-see-ums. Tests by the US Army have found Thermacell to be up to 98% effective within a 15 ft. x 15 ft. area. Thermacell Refills work with all Thermacell products. The Single Pack Refill comes with 1 butane cartridge and 3 repellent mats, providing up to 12 hours of protection. Refills are also available in a value pack which comes with 4 sets of refills (4 butane cartridges, 12 mats for up to 48 hours of protection). This product is registered by the EPA. Includes 1 butane cartridge and 3 repellent mats for up to 12 hours of protection. Features Repels up to 98%of mosquitoes, black flies, and no-see-ums. Each cartridge lasts up to 12 hours, and each mat lasts up to 4 hours Provides 15 ft X 15 ft area of protection. No Open Flame, No Deet Refills work with all ThermaCELL Mosquito Repellent products.