This Industrial Performance MPI400W/BU is a 400W metal halide HID lamp designed for dependable, high-output performance in commercial and industrial lighting applications. Featuring an EX39 base and BT37 clear glass bulb, it installs easily into compatible fixtures using an M59 ballast system. Producing bright 3800K white light, this lamp delivers strong, consistent illumination ideal for warehouses, manufacturing facilities, outdoor areas, and large commercial spaces. The base-up operating position ensures proper performance in approved fixtures. Rated for use in both open and enclosed fixtures and offering a service life of up to 20,000 hours, this HID lamp provides long-lasting reliability and reduced maintenance for demanding lighting environments.