'Castle Nut, Nut Style Round Slotted Nut, Basic Material Low Carbon Steel, Material Grade Grade 2, Fastener Finish Zinc Plated, Fastener Thread Direction Right Hand, Dia./Thread Size 5/16 In.-18, Fastener Thread Type UNC, Width Across Flats 1/2 In., Nut Height 17/64 In., Pin Dia. 5/64 In., Slot Width 0.12 In., Slot Depth 0.18 In., Nut Standards ASTM 563, Package Quantity 50'