Safety knife: The main difference with the standard safety knife is that the blade automatically returns, even if the blade mechanism is held in, when the pressure on the knife is removed. The blade is not lockable and can be changed without tools. Suitable for both right- and left-handed users. Cast aluminum front provides high durability. Is also equipped with a blunt knife tip to reduce the risk of stabbing injuries. Knife blade: SKB-8 18mm.