Socket Cap Screw M4 A4 Stainless DIN 316

A hex key (otherwise known as an Allen key) is required to fit these fasteners. Conforming to DIN 316 or ISO 4762. Also known as an Allen screw or Allen bolt, or simply a cap screw. Socket Head Cap screws are a more modern alternative standard machine fastener to the standard hexagon headed bolt or setscrew, as found on much modern machinery.