The TowSmart 4-Wire Flat to 4-Wire Flat Trailer Wiring Extension Connector has what you need to make electrical connections between your vehicle and trailer when towing. The one-piece construction with bonded wire provides stop, turn, ground and taillights. The ground wire attaches direct to the trailer frame for a solid ground connection. Features an ergonomic, durable plastic construction that is corrosion resistant to withstand extreme weather.