The TowSmart 7-Blade with Jacketed Cable Trailer End Connector with LED Wire Tester, SAE Auto Wire Code provides what you need to make electrical connections when hauling a trailer. The 7-blade trailer end connector offers a single housingdesign that plugs into your vehicle's electrical socket and splices into trailer wiring to provide a superior connection. The 7-blade connector is commonly used on RV trailers or large trailers and connects taillights, brake lights, turn signals, ground, electric brakes, auxiliary power, and reverse lights. Includes a built-in LED light tester to ensure alllight functions are properly working. It provides an ergonomic, durable plastic construction that is corrosion-resistant to withstand extreme weather.