The insert style for milling inserts vary depending on the type of tool holder, application, and operating conditions. The style is designated with a series of letters and numbers that indicate whether the insert is left or right hand, the shape or type, the width, and the thickness. For example, insert "R-390 11 T3" is a right-hand, style 390 insert used in Sandvik Coromant's Coromill 390. The insert is 11 mm wide and 3.97 mm thick. Another example is insert "SBEX 12 04", which is a square milling insert used in the AUTO-FS tool. The insert is 12 mm wide and 4.76 mm thick.
Each milling insert has a chipbreaker geometry that allows the insert to break off and evacuate chips most efficiently in specific applications, such as roughing and finishing, and in operating conditions related to the machine and workpiece material. Milling insert geometries for specific operations and conditions are designated with two or more letters at the end of the insert code. For example, PL chipbreaker geometry is designed for light milling of steel.