The CURT Electrical Adapter is an electrical device that allows a connection to be made between a mismatched trailer plug and vehicle socket. It easily plugs in your vehicle's electrical socket and usually requires no additional wiring. This CURT Electrical Adapter is designed to adapt a 7-way RV blade vehicle socket to fit a 4-way flat trailer plug. It features quality plastic construction, requires no splicing, and comes with an LED connector tester dust cover. Not only does this dust cover protect the socket from dirt, water, and road grime, but it also allows you to test your vehicle-side wiring connector to ensure your electrical systems are functioning properly.• Adapts a 7-way RV blade vehicle socket to fit 4-way flat trailer plugs• Simple plug-and-play design eliminates the need for cutting or splicing• 4-way flat output connects tail lights, brake lights, and turn signals• LED tester confirms proper function of vehicle-side wiring connector• Dust cover keeps connector clean when not in use LED tester confirms proper function of vehicle-side wiring connector Dust cover protects socket from dirt, water, & road grime | Curt 57245 Electrical Adapter with Tester (7-Way RV Blade Vehicle to 4-Way Flat Trailer)