Qualfast: M16X50 Flat Countersunk Nib Bolt C/W Nut (GR-4.6) Nib Bolt, Metric Steel - Grade 4.6 Flat Countersunk with Nut DIN 604/555 MPN: M16X50 Flat Countersunk Nib Bolt C/W Nut (GR-4.6) Attributes: Box Quantity: 25 Driving Features: Self locking Grade: 4.6 Head Shape: Countersunk Head Length: 50mm Material: Steel Standards Met: NF EN25-402 BS 4933 DIN 604/555 (1987) Surface Treatment: Plain System of Measurement: Metric Thread: Metric Thread Direction: Right Thread Size: M16