The stainless steel machine screw has a plain finish and a button head with a pin-in-star drive. Stainless steel resists corrosion and may be magnetic. The pin-in-star drive has a six-pointed indentation with a center pin that resists tampering by requiring a special driver to tighten or loosen the screw. The button head has short vertical sides similar to a pan head screw but has a low-profile rounded head instead of a flat top. The large bearing surface of the head reduces the chance of the screw embedding in the fastening material.
Machine screws are threaded fasteners that are typically used with nuts or drilled and tapped (threaded) holes. Machine 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 driver required to install and remove the screw.