Philips Mh1000/C/U Bulb Size = Bt56 Screw Base = E39
MFR Part# : GE Lamps MVR1000/C/U Multi-Vapor® Elliptical BT56 Quartz Metal Halide Lamp; 1000 Watt, 3700K, 65 CRI, Mogul Screw (E39) Base, 15000 Hour Vertical, 11000 Hour Horizontal Life, Coated