Mk 40 motors consists of a nozzle plate, four nozzleinserts, a fin-actuating mechanism, four fins, and a finretainer contact disc. The nozzle assembly for theMk 66 consists of the nozzle body, carbon insert, fins,contact band assembly, and weather seal.The fins are attached by pivot pins to lugs machinedon the aft part of the nozzle plate. The major difference between the nozzle and finassemblies used on the Mk 4 and Mk 40 motors is thetype of nozzle inserts used