Mercury - 5-Pin NMEA 2000 / CAN H Extension Harness 7 m 84-879171T08. OverviewBoat layouts rarely make wiring easy, and sometimes the sensor you need to mount ends up much farther from the backbone than you expected. The Mercury 84-879171T08 Extension Harness gives you seven full meters of extra reach, which is a nice sweet spot for bigger consoles or longer runs along the gunwale. It gives your GPS or IMU some breathing room so you can put it in the right spot without stretching or forcing the