Carriage and Timber bolts have no drive, and machine threads for use with a nut.
Carriage heads are large smooth and domed with no drive.
A corrosion resistant steel alloy. The most common stainless steel for general hardware use.
Solid bronze. An alloy of copper with greater strength and corrosion resistance than brass. Exact color varies.
Bolts with a very large flat head and machine threads for use with a nut.