A bolt is a type of fasteners with a head and a thread rod. It is usually used with nuts to fasten a stack of the parts together. According to material, we have carbon steel bolts, stainless steel bolts, and other material bolts. According to the standard, we have DIN, GB, ANSI, BSW, JIS standard bolts as well as the un-standard bolts. According to the function, we have hex bolts, carriage bolts, flange bolts and so on.