Is this a thing for finishing frets?

I saw this on the eBay site, although I can't find any for sale. In this article "option 3" appears to be a kind of sanding sponge:

http://www.ebay.com/gds/Ouch-Sharp-F...4719643/g.html

It looks like it would be good for my project which has an unbound, unfinished rosewood fingerboard. So, is this an actual thing? Has anyone tried this? I can't find a "Banana Yellow Fret Edge Buffer" anywhere.

Pretty sure there is no such animal.
A cheap and cheerful fret end file can be made from a flat diamond file from your local cut price tool shop or $2 store.
Simply grind one edge so it is smooth and slightly rounded and you have got yourself a fret end file.

Or you can spend a bit more and get a purpose made one from Stewmac.