Black Flag BB-40BLK 40-Watt Replacement, Black Bulb 40 watt replacement bulb fits Black Flag bug zapper model BZ-40DX, BZ-40MAX, and BZ-40BLK UV black light attracts and kills 40% more flying insects 20% more bulb life vs. competitors Measures: 1.78" L x .98" W x 13.15" H