The Portable Mosquito Repeller is an invisible shield of protection and is designed specifically for your favorite outside area with a twist of class that looks great on your patio or deck. It is virtually scent free and provides 15' by 15' Zone of Protection. Repels mosquitoes, black flies, and other flying insects. The heated mat releases repellent into the air. With no open flames, this product is extremely convenient and silent. Package includes 1 Butane Cartridge, that's good for 12 hours before refill, and 3 Repellent Mats, each mat lasts a maximum of 4 hours. No spray, no mess, no smells, no DEET!