OTC's 1.8 inch diameter Mack Kingpin Socket makes life easier for mechanics who work on Mack trucks. This socket fits the slotted adjusting screw in tapered kingpins used on most Mack trucks with 12,000 to 20,000 pound capacity front axles. Designed for use with a 1/2 inch square drive ratchet or breaker bar. Manual tool use only - not intended for use with impact tools. Ruggedly built tool features high-grade materials for a long service life under harsh shop conditions. Value is at the core of the OTC tool and equipment portfolio. For a simple repair or the most complex drivability concern, these award-winning tools universally solve problems faster, and at better value, than any other product line available. Whether it's a specialty tool or unique piece of service equipment, OTC provides top solutions to modern automotive service challenges while increasing technicians' productivity and shop profits.