This is a very useful tool for accurately mitering corners. Great for one-off binding and essential for high end production work. A small knob allows adjustment for 20 – 200 pt. board thickness. This jig allows butt joining of cloth, paper, vellum or leather. Perfect corners every time. Instructions for use included. Bronze and Delrin. The Delrin is dimensionally stable and it is easy to clean adhesives off. 5" cutting edge.