Compact and stylish, the Thermacell Patio Shield mosquito repellent device is the perfect guest for your parties in the backyard or at the cottage. With no batteries or cords, this people and pet-friendly system is powered by a compact fuel cartridge that can provide up to 12 hours of protection and it diffuses the scent-free repellent to create a protection zone of up to 15 feet thanks to the repellent mats that change colour when it is time to replace them.