For the backyard and beyond, the Thermacell Mosquito Repellent Perimeter System features two mosquito repellers that provide a 30-foot perimeter (15 feet each) for a total of 450 square feet of advanced protection against mosquitoes. Scent-free, no mess, and easy to install with no batteries or cords needed, the Perimeter System is ideal to surround your campsite, backyard, patio, or pool with discreet mosquito defense. Place a repeller every 15 feet around your entertaining area, insert a fresh cartridge and mat, and enjoy hours of distraction-free fun. Simply add additional systems to protect even larger areas. There are dual and flexible mounting options for landscape with an included travel bag for easy portability.