Wood screws have large threads for use in wood.
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.
A corrosion resistant steel alloy. The most common stainless steel for general hardware use.
A highly corrosion resistant grade of stainless steel. Ideal in salt water and chlorine environments.
A low carbon steel for general use. Zinc plated for moderate corrosion resistance.
Solid brass. An alloy of primarily copper and zinc with good corrosion resistance. Used mostly in decorative and electrical applications. Exact color varies.
Round heads are domed and look like half of a sphere. Phillips drive is x-shaped for installation with a Phillips screw driver.
Screws with large threads for use in sheet metal sometimes also used in plastic, fiberglass or wood.
Screws for wood to wood fastening applications such as decks, docks and ledgers, etc.