With the Swingline Stack and Shred 500M Shredder, you can shred as many as 500 sheets of paper automatically. All you need to do is insert a stack of 500 letter or legal size sheets with paper clips or staples into the auto feed tray, close the lid and walk away for the shredder to do its work. Moreover, the 500M auto feed shredder also features a locking mechanism where a user enters a 4-digit PIN code to interrupt shredding. Only an authorized person can enter the PIN code. Once the shredding process is finished only then any other person can use the shredder.