Sunlights Electronic remote ballast and 20.5"x20.75"x9.5" SunGro Horizontal reflector, lined with a 95% reflective aluminum insert for high luminescence, and louvered on one end and top. Optional tempered glass lens and 4 inch air cool fittings. Sunlight electronic remote ballast features an extruded aluminum housing that will never rust and has excellent heat dispensation qualities. Extremely efficient - 99% power factor and saves energy compared to HID ballast systems. Electronic ballasts will operate either HPS or Metal Halide lamps and are voltage specific, 120V or 240V and cannot be switched from one voltage to another. Choose a 400W 120V, 600W 120V and 240V, and 1000W 120V lighting system. 2-year rebuild or replace warranty.