This is a mass produced 1/4" bit that is sleeved to 3/8". I have been using this bit since the early 90's for refining and putting on the final touches of every piece that I have carved. It is not a shaping bit as it will ice up if pushed but it is more of a sanding bit. The silver burrs that I use, have been run on stones to dull them so that they behave the way I like. It has always been easier and faster to reach perfect surface with this bit rather than a more aggressive bit.