Our popular slam-lock can be added to any of our mailboxes, and is included on some models (senator and package box). If you receive several packages through the mail, then we suggest adding the popular slam-lock. Here is how this lock works: when you open the mailbox with your key, and remove the mail from the mailbox, you will leave the door slightly ajar. The mailbox will appear to be locked, and will have no mail inside. The door is then ready for the mail carrier to open using the included knob. The mail carrier places your mail and packages inside of the mailbox and then shuts the door and it automatically locks. You will come with a key to get your mail out. If you are gone several days, the mail carrier will still have access to the top slot to deliver your mail. The package box does not come standard with a slot, but can be added.