5/16″ Tube Nut. 1/2-20 UNF thread, 33 Degree seat. Standards Aerospace AN817-5, SAE AS5206-05. NSN 4730-00-603-0731 SPECS: AAJD Thread Class 3B AAJF Thread Direction Right-hand AARN Fabrication Method Any acceptable ACTA NUT Style Tube coupling ADEA NUT Height 1.062 inches nominal AGAV END Item Identification Aircraft application ASDB Width Across Flats 0.625 inches nominal BRQL Length TO Shoulder Any acceptable BSPX Smallest Inside Diameter 0.318 inches minimum and 0.321 inches maximum BZRR Thread Series UNF CMLP Thread Quantity PER Inch 20 CQJX Nominal Thread Size 0.500 inches CQRJ Nominal Tube Outside Diameter 0.312 inches CRRB Seat Angle 33.00 degrees nominal MATT Material Steel overall SFTT Surface Treatment Cadmium overall Get it here and save. L2B910344