Swingline 50-Sheet 350MD Electric Three Hole Punch, 1/4 inch Holes, GrayZip through standard punching jobs with this electric punch. Jam clearing mechanism ensures trouble-free operation. Clear view window on slide-out chip tray means you can see when it's full. NRTL approved. Metal and plastic. Sheet Capacity: 50; Operating Method: Electric; Number of Holes: 3; Hole Diameter: 1/4".