MS Square Head Set Screw is a type of fastener that is used to secure two or more objects together. It is a threaded screw with a square-shaped head, which is designed to be tightened with a wrench or pliers. MS stands for mild steel, which is a low-carbon steel that is commonly used in construction and manufacturing applications. The square head of the set screw provides a larger contact area for the wrench or pliers, making it easier to tighten or loosen the screw.