Unbreakable base stands up to the heavy use of busy offices and schools. Self-sharpening stainless steel blade. Patented automatic blade latch locks with every cutting motion. Finger guard protects the entire length of the blade. Torsion spring prevents blade from accidentally falling. Permanent 1/4" grid and dual standard and metric rulers help ensure proper alignment. 1 3/8" thick molded plastic base with non-skid rubber feet provides stability.