STANDARD METALARC lamps are an economical choice for a high efficacy, long life, white light source. 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 E39 base, BT37 bulb, enclosed fixture rated, universal burn, coated, 3700K light. Brand SYLVANIA MPN (Part No.) 64492 UPC 046135644924 Base Type Mogul (E39) Family Metalarc Bulb Color Coated Bulb Shape BT37 Case Quantity 6 Fixture Type Open or Enclosed (Restricted Position) Burn Position Universal ANSI Code M59/S Protected No Life Hours 20,000 Wattage 400 Watt Color Temperature 3700 Kelvin Length 11.5 in. Diameter 4.6 in. CRI 70 Lumens 36,000