Martin Yale W18 Premier Heavy Duty Paper Trimmer, 18" Cutting Length, Base Size 19.875w X 22d X 4h, Cuts Up To 20 Sheets at Once Permanent 1/2" grid and dual English and metric rulers Patented automatic blade latch that locks with every cutting motion Finger guard that protects the entire length of the blade Torsion spring that prevents blade from accidentally falling during operation Manufacturer's limited lifetime warranty on blade, one year for all other components The Original Green Paper Trimmer with a self-sharpening steel blade and heavy-duty wood base has an alignment grid and dual standard The original and still a favorite!. Fully-hardened self-sharpening high-carbon steel blade ensures a precise cut and long-lasting edge. Cuts mat board, cardboard, film, tissue and textiles. Safety features include a patented automatic blade latch that locks with every cutting motion