Screw-socket high intensity discharge metal halide bulbs * Ideal for metal halide pendant fixtures * 175-watt metal halide bulbs ideal for reef aquariums Screw-socket metal halide bulbs in a wide range of color temperatures and wattage to reproduce natural light conditions found in the ocean. Significantly brighter than other types of bulbs, metal halide bulbs can be used alone or with Actinic bulbs for a bluer effect. Use with any appropriately sized mogul socket metal halide lighting unit. 175-watt 20000°K Handle bulb by socket end only, DO NOT touch bulb.