Enjoy the outdoors without the mosquitoes with this Thermacell Mosquito Protector Refills Mega pack, which repels mosquitoes and midges for a total of 120 hours. This repellent is scent-free and its active ingredient is Allethrin, a synthetic version of a naturally occurring repellent found in chrysanthemum flowers. The pack includes 30 Mats and 10 Butane Cartridges - each cartridge provides 12 hours of protection. Fits all ThermaCELL models (appliances and lanterns).