The 18-8 stainless steel socket cap screw has a flat head with an internal hex drive and meets Deutsches Institut für Normung DIN 7991 specifications. The 18-8 stainless steel material provides strength and offers good corrosion resistance in many environments. The material may be slightly magnetic. The flat head is cone shaped for use in countersunk holes and has a flat top that fits flush with the mated surface. The internal hex drive, also known as a hex-socket drive, has a hexagonal slot that requires an Allen key driver, also known as a hex key or Allen wrench.
Socket cap screws are threaded fasteners that have a cap head with an internal socket drive for installing in areas with limited side clearance. These screws are available with a variety of head shapes, which determine how the screw interacts with the mating surface, and drive styles, which determine the type of tool required to install the screw.