When you're running multiple batteries and a deck full of electronics, clean power distribution isn't optional - it's the backbone of reliable performance. The Yamaha Marine Battery Isolator Lead - MAR-6CEIS-1L-ED is designed specifically for Yamaha 4.2L outboards, giving you 14 feet of flexible, marine-grade wiring with built-in 100-amp circuit protection. It's built to handle the real-world demands of offshore fishing, weekend cruising, or any setup where dual batteries and onboard accessories need to work together without a hitch.. This isn't just a basic wire harness. The heavy-duty lead is fully sheathed to stand up to vibration, salt spray, and the wear-and-tear that comes with life below deck. Factory-matched connectors make installation clean and straightforward, locking in with the precision Yamaha owners expect. And with the integrated 100-amp breaker, you're covered if a spike or short tries to take out your system.. Why it belongs in your rig:. 14-foot length offers plenty