ThermaCELL® Mosquito Repellent was patented by the Schawbel Corporation in 1999. Rigorous testing in extreme conditions by the U.S. Department of Defense proved ThermaCELL products work as advertised. ThermaCELL products are effective in warding off biting insects. The repellent creates a 15 x 15-foot zone of protection against mosquitoes, black flies, sand flies, and no-see-ums. This award-winning product has been recognized by leading entomologists, outdoor writers, and pediatricians as the solution to making outdoor activities enjoyable.