The heat generated by the butane cartridge is directed to a metal grill that is part of the design of the Lantern or Appliance. A small mat, saturated with repellent, sits on top of the metal grill. Heat vaporizes the repellent, allowing it to rise into the air.
The repellent is allethrin, a copy of a repellent that naturally occurs in chrysanthemum flowers. It repels mosquitoes, black flies, and no-see-ums, and will not harm humans or pets.
Within minutes after turning on the Lantern or Appliance, the repellent creates a 15 by 15-foot (225 square-foot) area of repellency, the size of an average out door garden or campsite. A few devices are perfect for an outdoor restaurant or seating area. All PCI’s Thermacell Mosquito Repellent products use the same refills, which contain both repellent mats and butane cartridges.