This reflector is designed to house high intensity discharge grow lamps. Growers can use either high pressure sodium (HPS) or metal halide (MH) grow lamps in a fixture like this. Lamps come in various wattages (power) - 250w, 400w, 600w, 1000w (most common) and 1500w.
The 8" diamater duct-ports on this air cooled reflector allow the grower to pass even more air over the lamp for increased cooling. Remember that the efficacy of your cooling is largely dependent on the temperature of the air you pass over the lamp.
Air cooled reflectors also confer another important advantage to the indoor gardener. You can remove a significant amount of heat from your garden without necessarily removing supplemented carbon dioxide. This is achieved by using a dedicated air-input for the reflector that draws air from outside the grow room.