The Black Flag 40 Watt Black Insect Killer Bug Zapper Replacement Bulb fits multiple Black Flag bug zappers and helps to give your Black Flag Bug Zapper the boost you never thought it needed. Thanks to its long lasting UV black light it attracts 40% more flying insects. Each bulb provides 20% more bulb life. It is quick and easy to install. The UV black light attracts the flying pests to the zapper making it easier for them to get zapped. Try out the Black Flag replacement bulbs and zap the bugs before they bite you.