OTC Tools OTC 1981 2 1/2 Pinion Locknut Socket. Socket has a 3/4" square drive opening, permitting the use of an extension and torque wrench to tighten locknut as required. Locknut removal and installation is simple, even when wide-rim wheels are involved, since a long extension may be attached to the socket to provide the necessary clearance. Socket is made of high-strength steel; openings resists round-out. Eliminates modifying standard socket to provide necessary clearance. Specifications Drive : 3/4" Useable depth : 3 Overall length : 4" Email for product availability.