Qualfast: M6 Knurled Thumb Nut High Brass CU3 Knurled Thumb Nuts, Metric, Brass Cu3, DIN 466. MPN: M6 Knurled Thumb Nut High Brass CU3 Attributes: Box Quantity: 25 Driving Features: Knurled Head Grade: Cu3 Leading Standard: DIN 466 Length: 15mm Material: Brass Cu3 Standards Met: DIN 466 Surface Treatment: Plain System of Measurement: Metric Thread: Metric Thread Direction: Right Thread Size: M6