250 Watt 14,000K , E39 Mogul ,T15 , Aquarium Lamp - Unprotected Arc Tube - 14,000K - ANSI M58/E - Mogul Base - Horizontal Burn Metal Halide Aquarium Light Bulb Probe Ballast Type Color Spectrum: 20,000k (Kelvin) Vivid Blue Operates on a HQI Metal Halide Ballast, Pulse-Start Ballast or Electronic Ballast Length: 6.40" , Bulb Shape: T9.5 Compatible bulb Guaranteed to meet or exceed manufacturers specifications