Jacobs 31048 6000-Series 1/2-Inch Soft Grip Sleeve Keyless Drill Chuck with 1/2 to 20 Threaded Mount 1/2-Inch capacity (1-1/2 to 13 mm) 1/2 to 20 Threaded mount Patented Soft Grip sleeve for easier tightening and better grip torque Patented ratcheting locking mechanism More comfortable