3/8 Inch Dia. Solid Carbide End Mill - Coated 3/8-Shank 5/8 LOC 2 OAL 4 Flutes - ALTiN Coated Diameter Tolerance: +.000"/-.002"ALTIN is a high performance coating for milling, tapping and drilling in stainless steels, carbon steels, alloy steels, titanium and cast iron. This coating is extremely heat resistant and can be used with or without coolant. It is exceptional in difficult to machine materials where adhesive wear is particularly high.