Martin Yale Automatic Letter Opener:This Automatic Letter Opener from Martin Yale is an ideal opener for moderate volumes. machine opens envelopes at an incredibly fast pace: up to 12,000 envelopes per hour. This hands-free operation automatically feeds and opens stacks of envelopes up to 3" thick and can open individual envelopes up to 1/4" thick. All user must do is place stack of envelopes that need to be opened in front of feeder and machine does rest for you.opened letters are stored in a convenient catch tray that can later be folded up and stored in back of base unit when it isn't being used. Blades are fully enclosed to protect fingers. scraps are ejected with envelopes into catch tray. Non-skid feet mean this 23 lb. machine is stable yet lightweight. It also has a power indicator light so user will always know when opener is on.