Hex nuts as a standard part, it should have its own general specifications, for hex nuts, commonly used standards are: GB52, GB6170, GB6172 and DIN934, for the main differences between them are: GB6170 thickness than GB52, GB6172 and DIN934 to thick, commonly known as thick nut.  In addition, the opposite side is different from the opposite side. The opposite side of DIN934, GB6170 and GB6172 in M8 nut series is 13MM, 1MM smaller than the opposite side of GB52 14MM. The opposite side of M10 nut, DIN934 and GB52 is 17MM, 1MM larger than the opposite side of GB6170 and GB6172.  For nuts of M12, the opposite side of DIN934 and GB52 is 19MM, 1MM larger than the opposite side of GB6170 and GB6172, 18MM.  For the nuts of M14, the opposite side of DIN934 and GB52 is 22MM, which is 1MM larger than the opposite side of GB6170 and GB6172, which is 21MM.  In addition, the nut of M22, the opposite side of DIN934 and GB52 is 32MM, which is 2MM smaller than the opposite side of GB6170 and GB6172, 34MM.  (GB6170 and GB6172 in addition to their thickness is not the same, the width of the opposite side is exactly the same) the other specifications in the absence of considering the thickness of the case, can be used.