Thermacell Patio Shield Mosquito Repeller creates a 15-foot zone of protection against mosquitoes Heat-activated technology powered by a safe and compact fuel cartridge that emits scent-free mosquito repellent to drive away mosquitoes No mess, easy refill with included unscented mosquito repellent mats that last up to 4 hours each and change color when its time to replace Repels mosquitoes withoutDEETbug sprays or lotions, smoke, flames, or strong scents, like citronella, with maximum protection in 15 minutes and no cords or batteries needed Plant-inspired, people and pet-friendly, synthetic allethrin formula inspired by natural repellent extracts and independently tested andEPA-reviewed for safety and effectiveness Keep enjoying outdoor activities with this sleek mosquito repeller on the porch, by the pool, while camping, at the lake, and more Includes one mosquito repeller, one 12-hour fuel cartridge, and three 4-hour repellent mats