Dunno. Not having much luck finding a 4-hole version of the plug (everyone else uses 3).
Buy the whole charger for 10 bucks:
https://www.aliexpress.com/item/1005001992618260.html
(though you'll be waiting a while for it to arrive)
Oh, here we go...
https://www.ebay.com/itm/GX16-GX20-G...n/184130683596
GX16, 4-pin female, at a guess...the number after GX refers to the diameter, in MM of either the plug or the socket...
this should clarify:
https://www.renhotecpro.com/gx16-connector-data-sheet/