Each of these sockets has 3/4″square drive opening, permitting the use of an extension and torque wrench to tighten the locknut as required Locknut removal and installation is simple, even when wide-rim wheels are involved, since along extension may be attached to the socket to provide the necessary clearance Sockets are made of high-strength steel; openings resist «rounding out» This item is a 3 pack of the base item OTC-1920.