5/8"-11 Plain Finish Grade 4 Finished Hex Nut / THREAD DIRECTION: RIGHT-HAND NUT STYLE: A12 HEXAGON WIDTH ACROSS FLATS: 0.489 INCHES MINIMUM AND 0.500 INCHES MAXIMUM NOMINAL THREAD SIZE: 0.312 INCHES PART NAME ASSIGNED BY CONTROLLING AGENCY: 5/16 - 24 HEXAGON NUT-END STAINLESS STEEL SPECIAL FEATURES: THICKNESS 0.273 MAX AND 0.258 MIN; DIMENSIONS: AMSE B18.2.2, SIZE 8 TO 10 PER AMSE B18.63; THREAD REQUIREMENT: ASME B1.1, UNC AND UNF, CLASS 2B; FINISH: PER ASTM A380