This is the boom system after the Benson Boom 85/55 version.  The Benson Boom II uses the Benson Boom style rear boom frame and the Ag-Chem style 60/80 boom arms.  The Benson Boom II was put into use later in the model year 2001.

Even though the Benson Boom II uses the benson Boom style rear boom frame, there are differences between some of the parts used on the rear boom frame assemblies between the Benson Boom 85/55 boom arms and the Ag-Chem 60/80 boom arms and also in model year 2001.  Consult the proper liquid system parts boooks to determine those parts when needed.