Structural Bolts are heavy hexagonal head bolts that are hardened alloy steel and are used in steel to steel applications and are typically shorter than normal bolts. Zero Products Inc.

Step Bolts are bolts with a larger than normal round head and a square neck that allows for a flat bearing surface. Zero Products Inc.

High Temperature Bolts are bolts that are made from certain alloy steels or stainless steels that can handle temperatures that are way higher than your average bolts. Zero Products Inc.

Countersunk Bolts are bolts with a flat head that tapers to the shank diameter so that it can be driven flush with the top of a countersunk hole. It may have a variety of drives such as a slot, Phillips, or Allen hex in the head. Zero Products Inc.

Left Hand Bolts are bolts with a reverse thread and is turned counterclockwise instead of clockwise to tighten. Used as a means to prevent bolt from coming loose in certain moving applications. Zero Products Inc.