This Replacement for Philips MS400/HOR is a 400W metal halide HID lamp designed for high-output, reliable performance in commercial and industrial lighting applications. Featuring an EP39 base and clear bulb design, it installs easily into compatible fixtures using an M59 ballast system. Delivering approximately 40,000 lumens of 4300K bright white light, this lamp provides powerful, consistent illumination ideal for warehouses, gymnasiums, retail spaces, and large-area lighting. The HOR ±45° burn position ensures proper performance in approved horizontal fixture installations. With a rated life of up to 20,000 hours and an 11.5" overall length, this HID replacement bulb offers long-lasting durability, dependable output, and reduced maintenance for demanding lighting environments.