Genuine OEM Mercury / Quicksilver button assembly. This switch-type component is used in the throttle control box as a factory original equipment part, ensuring proper interface with throttle/shift controls on select Mercury Marine outboard and stern-drive systems. Features: Direct OEM replacement for Mercury part # 891645A01 Factory-designed button assembly built to Mercury Marine fit, finish and durability standards Intended for use in throttle/shift control modules, providing reliable actuation of shift-or-gear functions Suitable as a backup or replacement when original button shows wear, fails to engage, or sticks May Fit / Common Usage:Listed under Mercury/MerCruiser controls and steering parts as “Button Assembly – Throttle / Shift” for many control assemblies. Because Mercury uses multiple versions of control boxes and cables, compatibility depends on the exact model of control and year. Verifying your control part number or diagram is recommended prior to purchase.