Martin Yale W15 Premier GreenBoard Wood Series Paper Trimmer, 14-3/4" Cutting Length, 20 Sheets Capacity, Heavy-duty 3/4"&nbsp;thick wood base, Ergonomic soft-grip handle Through-hardened steel blade cuts up to 20 sheets at once Permanent 1/2" grid and dual English and metric rulers help to ensure proper alignment Patented automatic blade latch locks with every cutting motion Finger guard protects entire length ofblade Torsion spring prevents blade from accidentally falling during operation