For large volume, high-speed processing. Automatically feeds and opens envelopes up to 1/4" thick. Opener accepts up to a 6" high stack of envelopes. Feeds, opens and stacks up to 17,500 envelopes per hour. Fully enclosed, self-sharpening blade adjusts for narrow or wide cut. Removable receiving tray. AC Operation. Blade Type: Concealed; Blade Material: Steel; Handle Type: N/A; Handle Material: N/A.