87121-ZW1-N00 RR (90) Mark - Overview. The 87121-ZW1-N00 RR (90) Mark is a genuine OEM part designed specifically for Honda marine engine systems. This component serves as a rear marking identifier, critical for accurate assembly and part recognition in marine applications. Engineered to fit precisely within Honda's marine rigging and accessories system, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Genuine OEM Honda component