The UltraGROW eco magnetic ballast is reliable on performance at a valuable price. It is compatible with most major lamps and offers stable output frequency to eliminate flickering. With powder coated aluminum fins and input voltage, this ballast is the perfect choice for all of your grow light projects! Contains a lamp indicator switch to change between metal halide and high pressure sodium lamps. Has separate plugs to switch 120v for 240v with no wiring. Also switch for High Pressure Sodium or Metal Halide bulb.