This high-quality replacement bulb is designed for the Flowtron BK-40 Bug Zapper, a powerful insect control device that uses ultraviolet light to attract flying bugs and then zaps them with an electric charge. The bulb emits a soft white light and has a wattage of 40W, making it an energy-efficient option for your bug zapper. Made of glass and featuring a contemporary style, this bulb is a great choice for anyone looking to keep their outdoor space bug-free. With 1-4 bulbs and a unit quantity of 1, this product is perfect for those who want a long-lasting, effective solution to their insect problem. Please note that this product contains Mercury and may cause cancer and birth defects or other reproductive harm.