Flat heads are countersunk (cone shaped under the head) with a flat top. Allen (hex socket) drive is a six-sided recess for use with an allen wrench (hex key).
The most common stainless steel for general hardware use.
The most common stainless steel for general hardware use. Black finish.
A highly corrosion resistant grade of stainless steel. Ideal in salt water and chlorine environments. More expensive than 18-8.
Black oil (plain) finish. A very high strength heat treated alloy steel.
A low carbon steel for general use. Chrome plated and polished for a mirror like finish.
Zinc plated for moderate corrosion resistance.