87121-ZV4-G00 Rr (15) Mark - Overview. The 87121-ZV4-G00 Rr (15) Mark is a genuine OEM part used in Honda marine engine systems. This part serves as a critical marking component on the rear (RR) side of specific Honda marine equipment, supporting clear identification and operational reliability. Designed to exact factory standards, it ensures seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Genuine OEM component designed specifically to fit