SYLVANIA 64188 - 400 Watt - BT28 - METALARC - Pulse Start - Metal Halide - Unprotected Arc Tube - 4000K - ANSI M155/E - Universal Burn - M400/PS/U/BT28 Color/Finish: Clear Color Temperature: 4,000K Average Lifetime: 15000 hours Lumens (light output): 22400 CRI: 65