The DIN32757 standard is a standard formulated by the German Standardization Committee DIN (Deutsches Institut fǖr Normung) for the shredding effect of paper shredders. DIN is the standardization authority in Germany, and its standards are internationally authoritative.
DIN 32757 classifies confidentiality into 5 levels:
Confidentiality Level 1 = 12mm strip
Confidentiality Level 2 = 6mm strips
Confidentiality Level 3 = 2mm strips (confidential)
Confidentiality Level 4 = 2 x 15mm particles (commercially sensitive)
Class 5 = 0.8 x 12mm particles (top secret)
Now the international shredder will be higher than the shredding effect of confidentiality level 5, and the confidentiality effect can reach 0.8X4.5 mm, which is extended to confidentiality level 6:
Class 6 = 0.8 x 4.5 mm particles (top secret) (this is an unofficial extension of the DIN 32757 standard)