The issue with a mail box like this in the building is that you cannot guarantee delivery to the recipient if you cannot guarantee it because the box is totally open and unlockable on the other side of the box such that it has no back wall because it was designed with an open back for mail insertion inside a room. It is open to anyone who could just walk by and enter the mail room and take the mail when the guard is on patrol. Most reputable buildings use a more secure system by law. There are other mail systems that we could utilize for more certainty of delivery as mandated by law. The one you see here has no open back wall for mail insertion. The back wall is solid metal. The mechanisms at the front can be opened only by the postal worker who has a special key.