Metric, ISO 7380, Steel self colour

These high tensile socket button screws are made out of 10.9 steel material with a self colour black finish to ISO 7380 and have a metric coarse thread.  They are sometimes known as Socket round head or dome head Screws.   They have a hexagonal recessed drive.  A hex key ( sometimes referred to as an Allen wrench or Allen key) or hex driver is required to tighten or loosen a socket screw. Socket screws are commonly used in assemblies that do not provide sufficient clearance for a conventional wrench or spanner.  These low profile rounded head screws are often used for their aesthetic qualities.