To be used with trailers with the same number of wires as the motorcycle. Wiring harness features an isolator module with a fused, separate circuit from battery positive to power the trailer lighting; works through built-in relays and prevents overloading of factory lighting circuit. 5-pin, die-cast, automotive-style connector. Mounts using mounting bracket that bolts directly to the safety chain bracket on current production Khrome Werks trailer hitches. An isolator is a must for 2009 and later H-D models pulling trailers with conventional incandescent lighting (higher amperage requirements than trailers with LED lighting).