DIN 32757 is the European standard for paper shredder security. There are 5 levels ranging from DIN1 to DIN5 in order of increasing security, reflecting the importance and/or sensitivity of the material being shredded. Every manufacturer uses this standard to define the level of security afforded by each model in its range.

The higher the security level, the smaller the shred size. Theoretically, it would be possible for a dedicated thief or fraudster to piece together the shreds of a document that has passed through a shredder at the lowest level of security. In fact this is unlikely because single documents are seldom shredded alone and shreds soon become mixed up in the shredder waste bin. However, DIN1 and DIN2 shreds with widths of 12mm and 6mm respectively or often still readable and can contain enough intelligible data to be of use to a thief or fraudster. This is why shredders working at those levels should only be used to destroy the least sensitive material.

Shred size is dependent upon the shredding mode used. There are two modes - Strip or Ribbon Cut and Cross Cut. Strip Cut shredders produce strips or ribbons up to the length of the document shredded. Cross Cut machines produce much shorter length strips down to the size of confetti at the highest security level. Strip Cut shredders only work at the lower security levels. Higher levels of security can only be attained by using Cross Cut technology.

Another useful benefit of the more secure shredders is that the smaller the shred size, the smaller the volume it packs down to. Therefore a DIN3 shredder (max strip width 2mm) will shred the same number of sheets into a much smaller volume than a DIN2 shredder (max strip width 6mm) would, which means that a higher security shredder needs to be emptied less often. The volume differences between the security levels are illustrated in the images below.

But none of these benefits come without cost. Smaller shreds need more work. This means either bigger, more expensive motors or the same motor as in the Strip Cut shredder running more slowly in the Cross Cut version or handling fewer sheets per pass, or often both.
 

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