Sylvania (64471) M175/U 175 Watt Metal Halide Light BulbSTANDARD METALARC lamps are an economical choice for a high efficacy, long life, white light source.nbsp;In addition, METALARC lamps have significantly higher efficacy than mercury vapor or incandescent and considerably better CRI than mercury vapor and high pressure sodium. This is a 175W, E39 base, BT28 bulb, enclosed fixture rated, universal burn, clear, 4200K light.nbsp;THIS ITEM MUST BE ORDERED IN CASE QUANTITY OF 6