Standard-duty cutter, designed to produce a fine score line to precisely break plastics, acrylic and laminates. Features built-in room for spare blades and a ratchet-wheel for secure blade extension and retraction, and unlimited blade positioning. Includes 1 reversable tungsten steel PB-450 blade inserted PLUS 2 replacement blades in the handle. For right- and left- handed use. How to scratch & break ? 1/ Place a plastic board on a flat surface and take straight strokes to make a score, deep enough to break by hand. Approximately one-third depth of the plastic board will be the rough standard. 2/ Snap off downward by hand along the score. 3/ Clean cut surface with the unsharpened edge, if necessary.