22 Watt Circline Ballast - HD22-120BA, Voltage: 120V Lamp Type: FC8T9, FC8T5 Fluorescent Circline Bulb, Dimension: L - 3-1/16" x D 2-3/8" x H - 1-1/4", Suitable For Damp Location, Type 1 Outdoor Use, Rapid Start Electronic Ballast, UL Listed.