These custom metric button socket cap screws are made using alloy steel material at 32-36 HRC with black oxide finish. The head diameter is 5.7MM and head height at 1.65MM, with a 2.0MM hex drive size. The overall length underneath the head is set at 6MM, of which 2.5MM is designed to be the un-threaded shoulder. Cold heading process was used to shape the head and the thread was rolled for optimal strength.