Provides everything your ThermaCell Mosquito Repellent Unit needs to provide hours of spray-free, invisible, and odorless protection from mosquitoes. Refill kit fits all ThermaCELL models. Each butane cartridge lasts up to 12 hours, with each mat providing up to 4 hours of protection. Refills can be stored for long periods of time, including between uses. Includes 12 mats and 4 butane cartridges (up to 48 hrs. of protection).