I have no idea where I got this (Foredom kit? Dremel kit?). I use it to grind little nicks in the edge of silver. It is fairly aggressive. It used to be a knife edge disc about 3/4" wide. It has about a 1/4" shaft. You see I have ground away most of it. It is a rough surface - I thought it was pumice, but maybe aluminum oxide. The real question is where can I get another one?!