The 72 inch Coralife Aqualight Pro Metal Halide Retrofit aquarium light is for reef aquariums. Retrofits are lighting systems made for installation into existing aquarium canopies. Please visit our Retrofit Lighting Chart page to identify the best light for your particular reef aquarium. A lens must be placed between the retrofit system and the tank to prevent water from splashing on the lamps and the included cooling fan must be installed in the canopy to keep the bulbs cool (and limit heat added to the tank). Features:Three 150 watt 10K HQI metal halide lampsFour 96 watt 03 Actinic compact fluorescent lamps Four 470nm Blue Moon Glow LEDsDimensions: 71" X 15" X 3" without mounting legsRemote ballastsLens coverTwo large 67 CFM 34.5 dB cooling fans w/ a 12-foot lamp cord and 6 foot power cord (must be installed in the canopy)Highly polished reflectorThree on/off switches (one for the compact fluorescent bulb, one for the metal halide bulbs, and one for the lunar lights)Instructions and installation guideRecommended Accessories:To keep the light cycle consistent, we highly recommend using a timer. To achieve the dawn/dusk effect we recommend the Coralife Aqualight Power Center Timer.Replacement Parts:We carry all the metal halide replacement lamps, compact fluorescent replacement bulbs and most replacement parts for the Coralife Aqualight fixtures