Purchase the 3 Geometric TOOLS AND SAVE $8! The brass imprinters have a pattern head of 13mm and is 5 inches long. They can be used anywhere on a bead for texture and are small enough that you can place a few imprints on a bead or just make small beads for sets or can he used on head pins. The 3 tools included in the geometric patterns are the Leonardo Concentric Circles, Leonardo Concentric Hexagon and the Leonardo Diamond Hex. (Boro pendant by Turtle Glass)