You'd probably be better oiff putting this in the Accessories and Other Musical Items forum. If you ask one of the mods nicely they will do it for you, I should think
Relisted at £25, and has four sets. .
But be wary, the main listing says "number of strings: four".
https://www.ebay.co.uk/itm/373557691887?ViewItem=&item=373557691887
I'm beginning to wonder whether some of these scamming gobshites people are members here. Some of these things drop off very soon after the membership starts threads about them.
I'd be astonished if you can put that on a body designed for a 20- or 21-fret neck. You'd have to move the bridge or rout the body.
The key to it is keeping the scale length the same.