Enjoy the outdoors more with the ThermacellA(R) Patio Shield Mosquito Repeller. The compact fuel cartridge powers the Mosquito Repeller for up to 12 hours. Simply add the repellent mat to the Repeller and enjoy a 15' zone of protection for up to 4 hours per mat. Perfect for keeping your campsite or patio pest free. DEET-free Mosquito Repeller 15-ft. zone of protection 12-hour fuel cartridge heats up repellent mats Mats last up to 4 hours each and change color when it's time to replace Unscented repellent Includes (1) repeller, (1) 12-hour fuel cartridge, and (3) 4-hour repellent mats