DIN 7991 refers to a specific standard established by the Deutsches Institut für Normung (DIN), which outlines the specifications for countersunk head screws with a hexagon socket. This standard is crucial for ensuring the uniformity and reliability of these fasteners in various applications, particularly in mechanical engineering and construction. The DIN 7991 standard details the dimensions, tolerances, and material properties required for these screws, thereby facilitating compatibility and interchangeability among different manufacturers. Adhering to this standard not only enhances the performance of the screws but also contributes to the overall safety and integrity of the assemblies in which they are used.