The 18-8 stainless steel socket cap screw has a button head with an internal hex drive, and meets American Society of Mechanical Engineers ASME B18.3 and American Society for Testing and Materials ASTM F879 specifications. The 18-8 stainless steel material provides strength and offers good corrosion resistance in many environments. The material may be slightly magnetic. The button head is round with a low profile and short vertical sides, and is suitable for light duty applications. 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.