Philips 100W USA H7 ALTO C100S54/ALTO (36872) High Pressure Sodium bulbs are intended primarily for use in enclosed luminaires. Initial Lumens 9400, Mean Lumens 8460, Rated Average Life 24,000 Hours based on 10 hours per start, ANSI Ballast Type S54. These Philips Alto HPS Lamps employ a mogul base and are designed with an ED23.5 bulb bulb.