87121-ZY6-J00 Rr (105) Mark - Overview. The 87121-ZY6-J00 RR (105) Mark is a genuine OEM Honda marine part designed to serve as a rear identification mark on Honda marine engine systems. This component plays a crucial role in accurately marking and identifying specific engine characteristics, offering seamless integration with Honda marine equipment. Engineered to factory specifications, it ensures reliable performance and durability essential for maintaining your boat's optimum condition.. Key