Mercury - Non-Power Trim Side-Mount Control Mechanical Control Box 8M0103454. Overview. There's a certain comfort that comes from a control handle that feels predictable every time you put your hand on it. This side-mount control keeps things simple and steady, the way many boaters like it-no extra electronics, just a clean mechanical feel. The long harness gives you room to rig the boat the way you want without fighting tight clearances. Out on the water, it's the kind of setup that just works,