The Thermacell R-10 Mosquito Repeller Refill 120-Hour Mega Pack effectively repels mosquitoes by creating a 15 ft. zone of protection when used in a Thermacell Repeller. This refill pack containing 30 repellent mats and 10 butane cartridges will last 120-hours total and is compatible with all Thermacell Repellers, Lanterns and Torches. Ideal for use while camping, fishing, gardening, hunting, around the backyard and more. Thermacell mosquito repellent products are powered by a Thermacell butane cartridge which directs heat to a small mat infused with the repellent Allethrin, a synthetic version of a naturally occurring repellent found in chrysanthemum flowers. Heat disperses the repellent creating the 15 ft. zone of protection. Thermacell protects millions of people from mosquitoes with no messy sprays or lotions, no odors, no noise, no DEET and no open flames. For best results, use on days with light or no wind (bugs are at their worst on these days) and allow 10-minutes to 15-minutes to form a complete zone of protection around the unit. Thermacell products are safe, effective and come with a 100% Satisfaction Guarantee. With Thermacell, Turn it on MOSQUITOES GONE.