Compatible UV Germicidal Bulb for Lennox 87N77 1076 18" Air System Fully Compatible UV bulb by LSE Lighting for use with Lennox 87N77 1076 18" Air System Ultraviolet Germicidal Light Bulb - Provides Air Disinfection Must be replaced every 12 month Length: 18" (436mm), Base: 4Pin-T5 Ceramic Base Glass Type: Quartz Glass Tube, Socket: Connectors are 4pin single ended {SE} circling