Mercury - Gen II Panel Mount Remote Control, Lock Bar, With Trim and Trailer Switch Outboard Control 883710A03. Overview. This control is meant for the bigger Mercury outboards that run external trim cylinders and need a little more going on at the handle. It's solid, mechanical, and feels like the controls most of us learned on years ago. The chrome handle has some weight to it, and the lock bar helps keep shifts intentional when you're close to the dock or lining up on the trailer. It's built