battery-powered insect repellant! By adopting the latest eco-driving system, it can be used throughout the season when insects are worrisome. The effect lasts for about 150 days when used for eight hours a day. There is no need to replace the battery in the middle of the season. When the battery runs out, it is time to replace the repellant. Since it is a battery/drug integrated cartridge, it can be replaced only once and installed with a single touch. Since it is battery-powered and does not require an outlet, it can be installed anywhere. Fragrance free and almost no audible sound means you can use this in your bedroom comfortably.