The Washer Seal, 6mm is the lowest priced item on this Oil Filter / Oil Pan schematic.
The Bolt,flange,6x28 is the most widely applied product in the CB750F 750 SUPER SPORT 1979 (Z) USA OIL FILTER / OIL PAN ( fourteen times ).
The Oil Filter / Oil Pan assembly is constructed from several parts from which the Pan,oil is the most expensive.