Mercury - Extension Harness 2-Pin Excitation and Ground 84-8M0176942. OverviewThis twenty-five-foot harness is built for boats where the rig center and isolator sit far apart and shorter runs just won't cut it. The extra reach lets you route the wiring in a calm, natural path instead of forcing tight corners or piecing together extensions. It helps keep the rigging bay cleaner and easier to make sense of when you open it up later. On bigger hulls, that extra length makes the whole job feel a lot