Marineland's Corner Tank System 5 Flourescent Bulb fits Eclipse Hex 5, Hex 7 and Corner 5 tanks, as well as all 11 watt aquarium lighting fixtures. It promotes aquatic plant growth while enhancing the natural colors of fish and plants. Energy efficient, it provides 5100K of natural daylight illumination and 6,000 hours of performance. 10 watt, 5.66 inches long, 1.80 inch diameter.