Qualfast: 5/16 BSF Hex Nut (GR-6) Imperial BSF (British Fine Standard) BS 1083 (1965) Material Steel Class 6 MPN: 5/16 BSF Hex Nut (GR-6) Attributes: Box Quantity: 100 Driving Features: Hexagon Grade: A Material: Steel Surface Treatment: Plain Thread: BSF Thread Direction: Right Thread Size: 5/16