2) Drill Guide Bushing: 3/4/5/6/7/8/9/10/11/12mm . 4) This is a set of drill guide tools for the fixation and centering while drilling and woodworking . 3) Anodized , to . Features: 1) Drill Guide Jig for Vertical Hole Drilling . 5) Made of Aluminum Alloy , strong strength and long durability