Shore Power Adapter by Marinco. Takes a regular 3 prong plug and changes it to locking three prong used on boats or in construction. Has locking collar and is marine grade for use in wet applications. Has a unique locking screw on the male end to keep it from dislodging. About $70 on Defender Marine. 20’ reach.
Combine this with another of my items and get a discount.
Leave a number, I’ll call.