Ushio 1000 watt Aqualite CWA 10,000K metal halide lamp with single ended mogul base screw type E39 base. Total bulb length including base is 11.42 inches. Aqualite CWA 10,000K lamps approximate equatorial daylight at 5 meters of ocean depth. This lamp is designed to operate on a standard domestic ballast. Ushio bulbs are made in Germany to the highest quality standards. Reliable and consistent for trouble free operation. 46000 luminous flux (lumens). 230 PAR value per watt. 90 CRI value. Ushio Aqualite metal halide lamps utilize proprietary rare-earth mixtures to provide the most consistent lamp color over the entire lifetime of that lamp. Ushio's arc tube forming process and coatings ensure that light degradation levels are kept to a minimum. For the best health of your aquarium and reef system, it is recommended that you schedule regular lamp changes depending upon your timing cycles and rated lamp life, generally every 10 to 12 months. Ushio bulbs have set the standard for high quality lighting that all other bulbs must follow. Bulbs have a 6 month prorated warranty.