Mercury - Active Trim Kit (Without Trim Pad) Mechanical MerCruiser Dual Engine 8M0129458. Overview. The Mercury Active Trim Kit (8M0129458) provides full automatic trim control for dual-engine mechanical MerCruiser sterndrives, giving you smoother handling, faster planing, and better fuel efficiency - all managed through your VesselView display instead of a physical trim pad.. Designed for 4.5L and 6.2L 300-350 HP mechanical sterndrives, the system continuously adjusts both drives based on speed