Rooting around in my bits and pieces box I unearthed an i-supply (230v -> 9VA at 50-60 Hz). It has a five pin output cable (with custom link to an old fashioned Apple connectIf. I recall it was a present to be used with my iPod back in late 1990’s.
I think there’s a reasonable demand for the S and H variants, but probably not for the I one you have. Worth checking to see if it can be converted caheaply enough for you to resell.