Metric socket button head, Class 12.9 alloy steel black oxide finish
Socket button head screw

Socket button head diameter is measured on the outside of the threads.

Metric socket button head diameter

Diameter and Thread pitch

3mm x 0.5mm 4mm x 0.7mm 5mm x 0.8mm 6mm x 1.0mm 8mm x 1.25mm 10mm x 1.5mm 12mm x 1.75mm 16mm x 2.0mm