Reese Connector 7 Way Round Car End in the Trailer Parts & Accessories department at Lowes.com
4-Way Flat Vehicle Side to 7-Way RV Blade Trailer Wiring Adapter 4TO7 – PlowPartsOnline
2 ft. 4 To 7 Pin Flat RV Boat Trailer Adapter Blade Plug Connector Tow Hitch 12V | eBay
Hopkins Towing Solutions Multi-Tow Trailer Light Wiring Adapter — 7 Blade to 6 Round and 4 Flat (Center Pin Electric Brake), Model# 47575
Amazon.com: Trailer Plug Adapters 7 Pin to 4 and 5 Flat Blade Trailer Connector for Trailer Tow Hitch, Weatherproof : Automotive
MaxxHaul 7-Way Round to 4-Way Flat Trailer Plug Adaptor with 18 in. Flexible Cable Extends to 36 in. 70086
Amazon.com: Trailer Plug Adapter 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 for Trailer Tow