Drill-hole Sizes: 1/4"; 5/16"; 3/8"; 7/16" And 1/2".
Drill equally space hole along the wood.
Adjustable to clamp on different thickness of wood boards from 3/8" to 2", quick operation, simple and convenient.
High quality aluminum alloy 6061(drill guide) and die steel(bushing), high hardness and strength, good wear-resistant and durable to use.It is a great tool set for both furniture factory and woodworking enthusiasts