all the letter shredders can shred paper clips and staples, while credit cards and CDs are supplied by special models, such as "7 Professional Card Shredder" and "CD Destroyer" to completely destroy CD data. Generally, in order to compete, low-end models on the market deliberately mislead consumers into thinking that cards and optical disks can be broken, while concealing the fact that the service life of the machines will be shortened after wrong use.