90508-ZZ5-M00 Washer Plain (6mm) - Overview. The 90508-ZZ5-M00 Washer Plain (6mm) is a vital rigging hardware component used in Honda marine engine systems. This plain washer provides a load-distributing function within the assembly, aiding in the reliable performance of your marine equipment. It supports critical mechanical connections by acting as a spacer and tension distributor, which helps in preserving the integrity of bolts and nuts used in the assembly. Designed to ensure seamless integr