Zoo Med's Coral Sun Actinic 420 T5 High Output fluorescent bulb promotes the growth of zooxanthellae algae, essential for the growth and well-being of all live corals and invertebrates. High output T5 bulbs provides more light than T8s, distributes the light evenly across the water surface and generates less heat as compared to metal halide lamps. Combine with Zoo Med's Ocean Sun for a more subdued "deepwater" tank effect or Ultra Sun for optimum viewing pleasure of live fish and corals. Use with Zoo Med's AquaSun T5 HO Aquarium Hoods. Note: T5 HO lamps can only be used in hoods designed for T5 HO Lamps. This high quality lamp is manufactured in Germany. Overall lamp length is 22"; 24W. Shipping weight: 1 1/4 lbs.