I owned a woodworking shop for 13 years.  For the last 7 years, a Sand Devil has lived at every bench in the shop.  I have used them, now I sell them.  The Sand Devil is a must have in the tool box of every professional & hobbyist. All you need is 3x21 belt sander paper; now get rid of all those ridiculous blocks of wood with sand paper stuck to them, get a Sand Devil and sand like a gentleman.