250 Watt, Ushio Compatible Replacement HQI 20000K 20K 250W Fc2 Aquarium Double Ended Metal Halide Bulb 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