Hex heads are six sided for use with a wrench.
The most common stainless steel for general hardware use.
A highly corrosion resistant grade of stainless steel. Ideal in salt water and chlorine environments. More expensive than 18-8.
A low carbon steel for general use. Zinc plated for moderate corrosion resistance.
A low carbon steel for general use. Hot dipped galvanized (A153) for very good corrosion resistance.
Solid bronze. An alloy of copper with greater strength and corrosion resistance than brass. Exact color varies.