THIS IS A HAIMER A40.140.18 HSK40A SHRINK CHUCK. KEY SPECIFICATIONS INCLUDE AN 18MM HOLE DIAMETER, A LENGTH OF 3.15 INCHES, AND A CLAMPING DIAMETER (D1) OF 18MM. THE TOTAL LENGTH (OAL) IS APPROXIMATELY 4 INCHES. OTHER DIMENSIONS ARE DIAMETER 2 (D2) AT 27.5MM, DIAMETER 3 (D3) AT 33.5MM, AND LENGTH L AT 1.7 INCHES. THE INTERFACE IS HSK-40.