Compatible Replacement for Flowtron BK-40D: Direct replacement BF-190 bulb designed for Flowtron BK-40D electronic insect killer, bug zapper, and mosquito control devices. Effective Anti-Mosquito Lighting: Emits light that attracts mosquitoes, flies, and other flying insects for efficient pest control in outdoor and indoor areas. Durable 10.25-Inch Construction: Long-lasting bulb designed to fit insect zapper devices with consistent performance and easy installation. Safe and Reliable Pest Control: Energy-efficient design helps maintain your bug zapper’s effectiveness while providing continuous mosquito and flying insect control. DISCLAIMER - We stand by our product’s quality. We recommend double-checking the bulb specifications before making a purchase. If you have any questions, please don't hesitate to contact us. We will be happy to help you. Compatible bulb with BF-190 BK-40D Bug Zapper Overall Length 10.25 Inches