Simply attach the power cord directly to your RV/boat’s marine-style 50-amp female connector. Using the hassle-free PowerGrip handle, plug the standard 50-amp male end to the power outlet. Can also be used to extend an existing power cord. Nice quality cord for power from your portable generator to exterior socket that feeds your tranfer switch.
https://www.amazon.com/BougeRV-Generator-Extension-Receptacle-Motorhome/dp/B07WBY5LPM