A flat socket cap screw is a type of cap screw with a fat cylindrical head, hexagonal or Allen drive hole and a countersunk bottom that runs flush with the installation surface. It is also known as a flat socket head cap screw or Allen flat socket bolt. A flat head socket cap screw is fully threaded up to the bottom and driven with a socket wrench.

Flat Head Socket Cap Screws are available in alloy steel with a black oxide finish and stainless steel316,18-8.