Amazon.com: OPT7 7 Pin to 4 Pin Trailer Adapter with Secure Tab, 7 Way Blade to 4 Way Flat Trailer Light Adapter, Connecter for Trailer Tow Hitch and Redline LED Tailgate Light Bar : Automotive
CURT LED Electrical Adapter (7-Way RV Blade Vehicle to 4 or 5-Way Flat Trailer) 57004 - The Home Depot
Trailer Light Electrical Adapter | StowAway
4-Way Flat to 7-Way Round Pin Connector Euro Trailer Hitch Light Plug Adapter | eBay