Hexagon Socket ISO Metric Thread Countersunk head used with a countersunk hole providing a flush fit Bright Zinc Finish – Electroplated to prevent corrosion DIN 7991 / ISO 10642 / BS 4168-8 / NEN 2359Kit contains: M5 (12, 16 and 20mm)M6 (x12, 16, 20 and 25mm)M8 (x20, 25 and 30mm)