THIS ISCAR CAT40 SEM 3/4X1.375 SHELL MILL HOLDER FEATURES A 3/4″ CONNECTION DIAMETER ON THE WORKPIECE SIDE AND A CAT SHANK TYPE WITH A SIZE OF 40. THE FUNCTIONAL LENGTH MEASURES 1-3/8″, AND THE CLAMPING LENGTH ON THE WORKPIECE SIDE IS .669”. IT IS DESIGNED WITH AN EXTERNAL COOLANT SUPPLY PROPERTY.