Thermacell Backpacker Mat-Only Refills effectively repel mosquitoes by creating a 15-foot zone of protection when used with the Thermacell Backpacker Mosquito Repeller. This Refill does not include fuel cartridges. Features: Includes 48 hours 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 hours each