Thermacell backpacker mat-only refills effectively repel mosquitoes by creating a 15 ft zone of protection when used with the thermacell backpacker mosquito repeller. This refill does not include fuel cartridges. Features: Includes 48 hr of mosquito protection refills Mat-only refill for use in the thermacell backpacker mosquito repeller No spray and no mess, scent-free and deet-free Active ingredient is allethrin, a synthetic version of a naturally occurring repellent found in chrysanthemum flowers Package contains - (12) repellent mats lasting 4 hrs each