Removes Studs from Engine Blocks, Exhaust Manifolds, Cylinder Heads and Other Applications. Allows for easy removal of studs. Tool has two holes, 1/2\" (14mm) and 3/4\" (19mm) for optimum fit, minimizing damage to threads. Range 3/8(10mm) - 3/4(19mm). Design allows tool to grip flush with mounting surface of the stud so it can grab studs that are broken off very close to the mounting surface. Use with 1/2\" square drive.