Venture 73531 - MS 400W/V/PS - 400 Watt Pulse Start Metal Halide Light Bulb, ED-37, Vertical Burn Position Base: Mogul (1.55" Diameter) Finish: Clear Burning Position: Vertical (Base up or base down) Lumens: 44,000; 4000K; CRI: 65 Average Life: 20,000 Hours MOL: 11.50"; ANSI: M155