Switch Start Metal Halide Protected Available in various bases and wattages. An efficient, protected "O" rated lighting solution that is suitable for open-rated fixtures. Ideal for both indoor and outdoor applications. Protective quartz shroud provides extra level of safety - shrouded arc tube for O open fixture rating.;No shut-off required- Ideal for 24-hours a day, 7-days a week operations (relamp fixtures at or before the end of rated life);Extended eyelet mogul base will operate in both standard and exclusionary sockets.;Satisfies the 2005 NEC for use in open luminaires;BT-56 base available in 1000 watts / ED-37 base available in 360 and 400 watts / ED 28 base available in 175 and 250 watts.;* Relamp fixtures at or before end of rated average life. The 2005 NEC states that luminaires that use a metal halide lamp shall be provided with either a containment barrier that encloses the lamp (historically referred to as an enclosed luminaire) or shall be provided with a means, typically a special lampholder, that will only accept ANSIType-O metal halide lamp. (Exceptionthis requirement will not apply to open luminaires with thick-glass parabolic reflector PAR lamps.) For more information regarding use ofType-O, S, and E metal halide systems, please refer to the NEMA white paper on this subject that is freely available at www.nema.org Ideal for manufacturing facilities, retail establishments and warehouses.