round meter socket 100Amps,120-240V 1phase,4 terminal,2 or 3 wire,fix hub size:1/2"to 1-1/4" aluminum Aluminum Die Casting elecrical Round Meter Box NUMBER DESCIRPTION FIXED HUB SIZE OS100B 1PHASE,100A,120/240V,4JAW 1/2'' OS100C 1PHASE,100A,120/240V,4JAW 3/4'' OS100D 1PHASE,100A,120/240V,4JAW 1'' OS100D 1PHASE,100A,120/240V,4JAW 1-3/4''