Yamaha Trim Tab Anode 67C-45371-00-00. Overview. The Yamaha 67C-45371-00-00 Trim Tab Anode is a genuine OEM sacrificial anode designed to help protect the lower unit of your Yamaha outboard engine from corrosion while also assisting with steering balance. Mounted on the lower unit behind the propeller, the trim tab anode helps counteract propeller torque, reducing steering pull and improving overall handling.. This trim tab is made from corrosion-resistant metal that sacrifices itself over time