BOS16421, 30 amp, 240 volt, 3 phase, 4 wire, fusible style bus plug, type BES / BOS, UL Listed assembly, complete with UL Recognized internal switch and components, suitable for use with OEM Bulldog / ITE / BD Series industrial busway systems, accepts Class R, H and K fuse types, direct substitute, fit and function for ITE OEM BOS16421, BOS16421R