The standard of DIN 934 has been eliminated in 2002. It is upgraded to ISO 4032 "Hex Nut 1" and ISO 8673 "Type 1 Hex Nut - Fine Teeth" standards, which have increase the thickness of nut. So the mechanical performance standard is ISO 898-2 specifies,which says the nuts load holding are to be increase as the specification increases. For example, the 8-grade nut is gradually increased from M5 855 MPa to M39 920 MPa. Because the size of the nut load holding not only based on the production process and materials, but also influenced by the thickness of the nut ( that is, nuts and bolts with the effective number of threads).
     Due to the DIN934 standard is still  the old side-to-side and thinner nut heights (relative to the upgraded ISO4032 and ISO8673), the mechanical performance is still in compliance with the old DIN267-4 "Technical delivery conditions for fasteners - Nut mechanical properties" standard. For example, "︱ 8︱" nut, regardless of its strength, nut size, mostly small, its guarantee load is constant value 800Mpa. Unlike ISO898-2 standard, the nut's guaranteed load is increasing as the specifications increase.
     Therefore, DIN934 in order to differ with mechanical properties of grades of ISO 4032  nut, DIN934 nut grade specified in the "︱ 8︱", to distinguish it from the ISO standard 8 intensity level.
     This is a special case of the DIN standard.