Improve lumen maintenance in an O rated lamp Improved lumen maintenance over standard switch start metal halide lamps.;Operates in both standard and exclusionary sockets due to the extended eyelet mogul base. Philips Protected Pulse Start Metal Halide O Rated Lamps are a better alternative to the standard switch start metal halide. O rated for safe operation in open fixtures*;Better choice over standard switch start metal halide.;Quicker restart/restrike time over standard switch start metal halide.;Improved lumen maintenance over standard switch start metal halide.;Extended eyelet mogul base will operate in both standard and exclusionary sockets.;ED-28 base is available in 175 and 250 watts / ED-37 base is available in 320, 350 and 400 watts as well as coated.;* Relamp fixtures at or before end of rated average life. 2 minute start /4 minute restrike vs. 4 minute start/15 minute restrike for standard switch start metal halide lamps. Ideal for manufacturing facilities, retail establishments, and warehouses.