Socket set screw is a type of screw that is designed to be used in applications where a secure and tight fit is required. It has a headless, cylindrical shape and is threaded along its entire length. The screw is typically tightened using an Allen wrench or hex key, which is inserted into a small socket or indentation in the top of the screw.

Socket set screws are commonly used to secure one object to another, particularly in situations where traditional fasteners may not be suitable, such as in machinery, appliances, and electronics. They are also used in applications where a flush surface is desired, as the headless design allows the screw to sit flush with the surface it is securing.

The threads of a socket set screw are designed to grip the material into which it is being threaded, creating a secure and permanent connection. They can be made from a variety of materials, including stainless steel, brass, and alloy steel, and come in a range of sizes and thread types to accommodate different applications.