Hexagon socket head cap screws, also referred to as hexagon socket head bolts, cup head screws and socket head socket screws, are called differently, but they represent the same meaning. Generally used hexagon socket head screws are 4.8, 8.8, 10.9, and 12.9. Also called hex socket screw. Its head is a hexagonal head and also a cylindrical head. There are stainless steel and iron according to material. Stainless steel has stainless steel SUS202 hex socket head screws. This is a stainless steel common material. There are stainless steel SUS304 hex socket head screws and stainless steel SUS316 hex socket head screws. According to the strength grade of the hexagon socket head screws of iron, there are 4.8 grade hexagon socket head screws, 8.8 grade hexagon socket head screws, 10.9 grade hexagon socket head screws, and 12.9 grade hexagon socket head screws. 8.8-12.9 grade hexagon socket head screws are called high strength and high grade hexagon socket screws.