The Thermacell Patio Shield Mosquito Repeller effectively repels mosquitoes by creating a 15-foot zone of protection. This compact, easy-to-use and stylish device will look great on any patio or deck while it works to keep pesky mosquitoes from biting and bothering your guests. It provides proven Thermacell fuel-powered technology, in a compact and stylish design for patios, decks, and more. It is ideal for use while entertaining and includes integrated mat storage. The Patio Shield Repeller is cordless, portable, lightweight, and designed for easy use. Simply insert a repellent mat and twist in a fuel cartridge, then turn it on. The fuel creates heat. A view window lets you check for an orange glow to ensure the heat is on. Heat activates the repellent in the mat. After 15 minutes, a mosquito protection zone is formed. The repellent mat turns white after about 4 hours indicating it’s time for the mat to be replaced.