For the backyard and beyond, Thermacell Refills keep your Patio Shields, Lanterns, Torches, and other fuel-powered Thermacell Repellers fueled for the long haul, no batteries or cords needed. Always be prepared by keeping extra cartridges and mats in your tent, backpack, garage, or tackle box ready when you need it. Thermacell Mosquito Repellent Refills pack comes with 120 hours of mosquito repellent and fuel.Repels mosquitoes, black flies and no-see-umsWorks with all Thermacell repellers, lanterns and torchesEach butane cartridge lasts for up to 12 hoursEach repellant mat lasts up to 4 hoursActive ingredient is allethrin, a synthetic version of a naturally occurring repellent found in chrysanthemum flowers
