Specs: 3/16" shank, 0.180" cutting diameter, 4 Flutes, 0.115 neck diameter, 1" reach depth, 2-1/2" overall length. Use for milling 1/4" diameter threads or larger. Internal or external threads from 20-56 TPI. A 0.005” Radius has been added to this tool, and quantity is 5 pieces.