They are of professional use quality, and I am very pleased with the wheels. They are of the best construction and sewing that makes them strong and strudy at high speed polishing. I hope that Eeastwood Co. comes up with some kind of plastic insert bushing ,so they can be made universal in different size shafts on buffers, say from 1/2" to 3/4" size shafts, plastic tube type bushings would work. Thanks Chale32.