3/4 x 16 TPI Self-Centering 4-Jaw Chuck Jaws will expand and grip in a 2-3" dovetailed recess 3/4" x 16 TPI Self-Centering Holds round stock between 1-5/8" and 2-3/4" or square billets 1-1/8" to 2-1/8" in size Chrome-plated body