Mercury - SC100 Data Harness 10-Foot SmartCraft Link Extension 84-880756T10. Overview. When SC100 gauges need to sit farther apart-or when the wiring has to cross a wider helm-this harness gives you the reach to make it work without forcing anything tight. The Mercury 84-880756T10 SC100 Data Harness adds a full ten feet of SmartCraft extension, making it easy to run the link cleanly through console chases or behind larger panels. It keeps the wiring relaxed, the layout cleaner, and the gauges co