Thermacell fuel cartridges keep your Patio Shields, Lanterns, Torches, and other fuel-powered Thermacell Repellers (except the Backpacker) fueled for the long haul, with 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. This Thermacell Mosquito Repellent Refills pack comes with 48 hours of fuel cartridges.