GE's Mercury Vapor high intensity discharge light bulbs provide long-lasting performance and good efficacy. The deluxe white coating provides better color rendering versus uncoated Mercuy Vapor light bulbs and rated to last 20, 000 hours. Use this HID 175-Watt Mercury Vapor ED28 shape light bulb only with H39 ballasts in residential and commercial security lighting, industrial, roadway and parking lot lighting.