DIN 126 specifies the dimensions of split pins, also known as cotter pins, which are used to secure fasteners such as bolts and nuts in mechanical applications. The standard outlines the various sizes and dimensions of these pins, including the diameter, length, and the distance of the split. It also provides guidance on the materials and finishes that can be used for manufacturing split pins. This standard ensures that split pins manufactured according to these specifications will fit and function properly in a wide range of mechanical assemblies, contributing to the safety and reliability of machinery and equipment.