TECHNIKS PSS-40 RETENTION KNOB SOCKET FITS ALL 40 TAPER (CAT40 BT40) PULL STUD Our Part # TEC-PSS-40 Square drive- 3/8" drive x 3/4" flats Made of high grade tool steel This will fit all of your 40-taper retention knobs Recommended torque is 80-90% of value given by Techniks (76 ft/lbs)