The knife is designed for people working in places where cardboard packaging is often cut: in supermarkets, warehouses, on technological lines, etc. The blade, after being ejected and driven into the cardboard, remains in the extended position as a result of friction against the material being cut, but retracts immediately after loss of contact with the material being cut or when you let go of the knife from your hand. Thanks to this, it eliminates the risk of leaving the knife with the extended blade. Comfortable handle made of high-quality ABS, blade guide made of stainless steel and a strong spring retracting the blade ensure long use. The knife can be fitted with two types of trapezoidal blades and a hook blade. Its design allows for very easy adaptation to work for left-handed people, changing the blade does not require additional tools.