ASME B 18.2.1 Hex Cap Screw UNC Gr.8 Steel

Strength class Gr.5 (~8.8).
Material: steel.
Uncoated (St).
Coarse thread (UNC), Unified National Coarse.
Fully or partially threaded depending on length and diameter.
NOTE! The fastener length shown in the product name is given in millimeters!

A hex bolt (nut head, hex head bolt) is the most commonly used screw fastener in machine and equipment installations.
The shape of the head provides a good grip, and the tools used for installation provide a secure hold for tightening the fastener to the correct torque.
In everyday language, a hex bolt is known by many names, such as bolt, screw, machine screw, nut head screw, threaded bolt, or threaded screw, to name a few of the most common.
Available materials include uncoated steel (St), zinc-plated (bright zinc, ZN, zinc), hot-dip galvanized (KS, HDG), stainless steel (A2), and acid-resistant steel (A4).