High security cross-cut shredders, suitable to shred "Classified" and "Top Secret" documents. Carbon hardened cutting knives. High precision design of cutting knives allows high shred loads with low power consumption. Motor thermal protection. 24 hours continuous duty motor: no duty cycle or timed cool down period. The HS-6 model can shred a paper sheet in about 20.000 microchips which become absolutely unreadable even if special electronic devices are used.