Diameter: #4
Length: 3/16"
Material: Stainless Steel
Head Style: Headless (Hex)
Thread Size: 40 (Coarse)
Thread Length: Full
Hardness: 18-8
Style: Socket
Type: Set Screw

Box of 20.

A set screw is a type of screw generally used to secure an object within or against another object, normally not using a nut. The most common examples are securing a pulley or gear to a shaft.