Castle Nut, Finish Zinc Plated, Material Steel, Material Grade/Class Grade 2, Thread Size 9/16 In. -18, Hex Width 7/8 in, Hex Height 31/64 in, Hex Type Standard Hex, Lock Type Slotted Castle, Material Quality Standards ASTM 563, System of Measurement Inch, Thread Direction Right Hand, For Pin Diameter 9/64 in, Maximum Slot Width 0.18 in, Pack Size Small Pack, Package Quantity 25. This item has been restricted from sale in the following state (s): []