Keeping the pesky mosquitoes away without putting anything on your skin is now possible with the Thermacell Patio Shield mosquito repellent device. Scent-free, DEET-free, silent and easy-to-use, turn on this compact repeller to create a 4.5-meter (15-feet) zone of protection whether you are sitting poolside, on a hammock or at a table with guests in the backyard. This device provides up to 12 hours of protection and comes with a fuel cartridge and 3 repellent mats with a maximum of 4 hours repellency per mat and turn from blue to white once empty so you can know when it needs to be replaced.