This Sylvania 54263 lamp has a T5 bulb shape and a G6.35 base type. It operates with 150 watts and 24 volts and will typically last an average of 50 hours. This bulb has a base down/horizontal burning position. The 54263 bulb's corresponding ANSI code is FCS This lamp is most often used in microfilm readers and medical equipment. It can potentially be subsituted with the FDV lamp.