Lumatek LK6240 240V HPS-MH Dial A Watt Dimmable, 600W-400W-300W, 1 Lamp More lumens generated per watt of electricity consumed, this ballasts have increased efficiency over magnetic ballasts They lose fewer watts from the power supply to the lamp; this is a power factor of 99 percent; the high frequency output results in low power loss This ballasr features fast start-up they reach full brightness quickly, completely silent, small compact design, produce less heat Fully interchangeable, this ballasts can light both HPS and MH bulbs Compatible with smart volt power cords; this product comes with 5 year warranty