Designed for the adventurer, the Thermacell Backpacker portable mosquito repellent device is easy to use and provides hours of mosquito defense. Scent-free, this device is effective up to 15 ft (4.5 m). With no batteries or cords needed, it utilizes the same camping gas canisters (not included) that backpackers and campers commonly have in their bag already. With its 4.0 oz. lightweight design and its compact size, it provides dependable performance up to an elevation of 7,000 ft (2,133 m). Unscented repellent mats last up to 4 hours each and change color when time to replace. The Backpacker is mess-free and easy to use, perfect for the enjoyment of the outdoor enthusiasts.