Black Flag 40W Outdoor Electric Insect Killer Replacement Black Bulb, Black Light. Black Flag is the consumer recognized brand in the Bug zapper category. Our superior voltage lets you see the lights and hear the quiet zaps while protecting your yard. Black Flag Bug Zappers use new advanced circuit board technology to deliver superior performance and use 30% less energy and provide 20% more bulb life compared to competitors. Replacement bulb for black flag bug zappers. Blacklight attracts/kills 40% more flying insects. Easy to install.