Flat heads are countersunk (cone shaped under the head) with a flat top. Phillips drive is x-shaped for installation with a Phillips screw driver.
Also known as A-2 stainless, 18-8 is the most common grade of stainless steel for general use.
A low carbon steel for general use. Zinc plated for moderate corrosion resistance.
Screws with an Allen wrench drive.
Screws with machine threads for use with a nut or in a tapped hole.