The socket cap screw has a smooth surface and a hexagon head. Stainless steel 18-8 material provides strength and 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 applications. The internal hex drive, also called a hex drive, has a hexadecimal slot that requires a hex key, also known as a hexagram key or hexagram. Hexagon head screws have cylinder head screwdrivers and hexagonal actuator for mounting in areas with limited lateral shaping. 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.