CMT 529.445.31 Plug Cutter, 1-3/4-Inch Minor Diameter, 2-7/32-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.