Industrial Lighting Solutions Ultraviolet Classic Compatible UV Sterilizer Replacement Lamp Effective hours rating: 12, 000Hrs ultraviolet germicidal light bulb Cross reference: Ultraviolet a20057 classic 57 watt Bulb type: T5 style quartz glass Base type: 4Pins one end, approx. 17. 5" In length 1% compatible with aqua ultraviolet a257 classic up system