Shrink Fit Tool Holder, Hole Dia. 3/8 in, Taper Size HSK63A, Shank Dia. 3/8 in, Projection 3.3500 in, Nose Dia. 0.9400 in, Coolant Fed Coolant Through, Balanced to RPM 24,000, For Use With Shrink Fit Tools, Includes Backup Screw