MaxxHaul 70086 7-way Round To 4-way Flat Trailer Plug Adaptor with 18-in Flexible Cable Which Extends To 36-in in the Trailer Parts & Accessories department at Lowes.com
Amazon.com: Oyviny 4-Way Flat to 7-Way Round Blade and 4 Way Trailer Wiring Harness Adapter Vehicle-Side 4 Pin to Trailer-Side 7 Pin and 4 Pin Dual-Output Connector with Mounting Bracket for Truck
20134 --- 5th Wheel 90 degree Adapter Harness -7-Way Flat Pin U.S. Car Connector Assembly 9'
Europe To US Trailer Light Converter for European 7 pin to American 4 pin Adapter Wiring Connector Trailer Plug Accessories - AliExpress