DIN 961 specifies the characteristics of hexagon head screws with fine pitch thread and low head, made of steel or stainless steel. These screws are primarily used in machine parts and in aeronautical or aerospace applications where high strength and durability are required. The standard covers the dimensions, materials, markings, and technical specifications of the screws, ensuring uniformity and compatibility across different manufacturers. DIN 961 plays a crucial role in ensuring the safety and reliability of machinery and equipment by establishing clear guidelines for the production and use of these specialized screws.