The Thermacell mosquito repellent unit is just what you need to keep mosquitoes and other annoying insects away while hunting or spending time outdoors. The unit works by heating a mat saturated with mosquito repellent, which propels fumes in the air, creating up to a 15' x 15' mosquito free zone. Thermacell is EPA approved and odor-free. This appliance will also repel black flies, no-see-ums and sand flies. Included with the unit are 3 repellent mats and 1 butane cartridge. This combo also includes a Thermacell holster. The holster will allow you to clip the unit to any tree branch or even to your body, for easy transportation and protection. The holster also features 2 accessory pockets to hold extra butane and mats.