CURT 4-Way Flat Connector Socket with 60" Wires (Vehicle Side) 58040 - The Home Depot
Uriah Products 4-Way Male Flat Trailer Wire Connector
CURT 4-Way Flat Connector Plug & Socket with 12" & 48" Wires (Packaged) 58355 - The Home Depot
Uriah - 2 Way Flat Trailer Wire Connector - Murdoch's
Hopkins 12-Inch 2-Flat Trailer Electrical Connector for RVs - Corrosion Resistant Terminals, 12-Volt Accessories in the Trailer Parts & Accessories department at Lowes.com