This is the outdoor lantern that uses d-cis/trans allethrin, a repellent field-tested by the Walter Reed Army Institute of Research, proven to repel up to 98% of mosquitoes. Sold to military personnel worldwide, the lantern uses a synthetic repellent made from a naturally occurring insecticide found in chrysanthemum. This lantern uses a 2 1/2" x 1 1/2" mat saturated with the repellent that rests on a metal grill on top of the lantern; a butane-fueled heater vaporizes the repellent to create a 15' x 15' zone unbearable for mosquitoes and other biting insects. Eight LEDs inside the lantern produce an efficient glow. Includes two butane cartridge and six ThermaCELL Mosquito Repellent mats. Butane cartridge lasts up to 12 hours; each mat lasts up to four hours. Requires four AA batteries. 11 3/4" H x 5" W x 5" D. (13 oz.)