Socket Shoulder Screws are screws that have an unthreaded shoulder below the head to act as a fulcrum for a lever pivoted on it. Variants included in this assortment range 25mm thru 50mm in length and come in M16 and M20 diameters. Full assortments of #33793 contain seven (7) refills comprised of Hillman item numbers #33794 - #33800.