HHIP 3701-2499 1/64-1/2 Inch MT3 Integrated Drill Chuck Clamping Capacity 1/64~1/2"; Shank MT3 Integrated design maximizes rigidity & accuracy Integral Shank is more compact than a combined drill chuck and Arbor and eliminates the chuck slipping on its arbor; T.I.R.? .0025"