A set screw, also known as a blind screw or a grub screw, is a type of screw generally used as a detent to secure an object within or against another object, usually without using a nut. The most common examples are securing a pulley or gear to a shaft.
SS304 stainless steel set screws are chemical resistant and may be mildly magnetic. They have a thin edge that digs into the contact surface for a secure hold. The length listed is the overall length.