Genuine Jacobs Drill Chuck 3/64" - 1/2" 1.5 - 13 mm Capacity with MT3 Morse Taper 3 Arbor & Key Genuine Jacobs 1.5mm - 13mm 3/64" - 1/2" capacity drill chuck Morse Taper #3 threaded arbor Includes original Jacobs key, may be thumb or T style, as available.