Amazon.com: 4 Flat to 7 Blade Trailer Light Adapter, Wiring Reverse Plug Connector with Mounting Bracket for Car Truck RV Side to Trailer Side Towing Solutions, RV 7 Pin to 4 Pin
Seven-Way Blade to 4-Way Flat Trailer Adapter
Amazon.com: Miady 4-Way Flat to 7-Way Round Blade Trailer Adapter Wiring Plug Connector with Mounting Bracket : Automotive
TowSmart 7-Way Blade to 4-Way Flat Trailer Light Wiring Adapter 1415 - The Home Depot