This jig is simple, accurate and quick to use. No measuring or calculating is necessary. It is great for miter, butt and edge joints. Also works well as a mortising guide. Offset holes are easy, just add a spacer block. Anodized aluminum body with hardened steel guides. The jig handles material from 1/4-Inch to 6-Inch thick. Two extremely accurate guide holes are tapped for the supplied bushings to let you drill three sizes of holes on 3/4-Inch center with one clamping. Includes two bushings each; 1/4-Inch, 5/16-Inch and 3/8-Inch, plus two fixed holes measuring 7/16-Inch and 1/2-Inch .