The requirements and testing procedures are developed by testing the firmness, corrosion resistance and free rotation displacement of the hardware under simulated daily use, before and after durability testing; you can see some examples of testing.
In order to maintain the interchangeability of locks and hardware standards, some national standards are inevitable.
This is why some of the door handle specifications are compatible with the DIN 18255 lock standard, while the DIN 18252 European lock core standard is replaced by the DIN 18255 standard, which is called the retention standard in the DIN EN 1906 standard as an appendix.

All Lishi Construction hardware products meet the DINEN1906,4 standard (effective in May 2002), as well as the standard that DIN 18255 is still in effect; in addition, our products have been used by the construction industry for a long time.