This set includes a wood top pin vise and two cup burs. One bur has an inside diameter of 1.2mm and the other is 1.8mm. These cup burs are used for rounding the ends of various sizes of wire. The pin vise can also be used for other tasks, more easily, because of the round comfortable head.
I use this tool to round the ends of handmade earwires.....very quick, very useful :) There is one collet under the handle and one under the tip.