The Thermacell Backpacker Mat-Only Refills offer effective mosquito repellency, creating a 15-ft zone of protection when used in tandem with the Thermacell Backpacker Mosquito Repeller. They provide a convenient, no-spray, no-mess solution. These refills are scent-free and DEET-free, ensuring a comfortable and safe environment. It\'s important to note that these refills do not come with fuel cartridges. The active ingredient in these refills is Allethrin, a synthetic compound that emulates a natural repellent found in chrysanthemum flowers. This package includes 48 hours\' worth of mosquito protection refills, with the pack containing 12 repellent mats that each last for 4 hours.