CMT 529.508.31 Plug Cutter, 2-Inch Minor Diameter, 2-15/32-Inch Diameter, 5/8-Inch Shank 4 Cutting Edges, 6-5/16-Inch Overall Length. Max suggested RPM: 150 on hardwood,200 on softwood. Made of alloyed steel, long-lasting cutting performance. For making plugs in soft and hardwood.