AC423R, 100 amp, 240 volt, 3 phase, 4 wire, fusible style bus plug, type BEC / AC, UL Listed assembly, complete with UL Recognized internal switch and components, suitable for use with OEM Armor Clad industrial busway systems, accepts Class H, R and J fuse types, direct substitute, fit and function for OEM AC423R, AC423RJ, AC1423, AC1423R, AC1423RJ