A4 set screw with hex socket and cup point DIN 916 is manufactured in accordance with the DIN 916 standard. The set screw is designed with a hex socket at one end and a cup (hollow) point at the other. It is typically used in applications where two or more materials need to be fastened together by means of threads. A4 acid-resistant stainless steel gives the set screw good corrosion resistance and makes it suitable for use in environments with high humidity or other corrosive conditions.