Martin Yale - PRE1632 Electric letter opener is ideal for mid-size to large businesses with an automatic-feed, high-volume capacity and hands-free operation. The letter opener automatically feeds and opens a 1-3/4" tall stack of standard-size business envelopes at a speed of up to 7,000 envelopes an hour. Simply put the envelopes into position and turn on the machine. Blades are fully enclosed to protect fingers. Letter catch tray folds for easy storage. Electric letter opener also offers nonskid feet to keep the machine in place.