Work smarter not harder sums up the Powerbuilt Stud Remover. It helps to easily remove broken, stubborn, and stuck studs from 1/4 inch to 3/4 inch diameter via its ingenious cam design. The knurled roller uses cam action to automatically close to the right stud size and grip the stud tightly for easy removal and minimizing damage. Just attach it to a 1/2 inch drive ratchet or flex handle and turn to tighten the cam, then turn until the stud is removed.