For the backyard and beyond, the Thermacell Mosquito Repellent Perimeter System 3-Pack is easy to install and provides advanced mosquito protection. Odour-free, spray-free, and DEET-free, the Perimeter System is an ideal bug spray alternative to surround your backyard, patio, or pool with discreet mosquito protection. The 3-Pack mosquito repeller system creates 13.5 meters of perimeter area mosquito protection (4.5 meters per repeller), or 63 sq. meters total. The system comes with 3 ground stakes, 3 post mounts, 3 mosquito repellers, nine 4-hour repellent mats, and three 12-hour fuel cartridges. Simply place a repeller every 4.5 meters for a continuous protection area and add additional repellers to protect larger areas. Once you have planned out the perimeter around your entertaining area, insert a fresh cartridge and mat, and enjoy hours of mosquito-free fun. Count on Thermacell to make outdoor time even better.