Gaines Classic Faceplate column mailboxes include a "standard" mail slot of 3" high x 10" wide. While the large size will not prevent unwanted hands from entering the mailbox, it does provide for large bundles of mail and small packages to be easily inserted into the mailbox. For those only moderately concerned with mail theft, this option may provide the best option as the presence of the lock typically provides some level of deterrence while not limiting the functionality of the mailbox. If security is a concern, the high security option restricts the opening by half, to 1-1/2" high x 10" wide. This option is factory installed and must be ordered at time of purchase, however, it can be removed by the user if you decide you'd prefer the larger mail slot. High security option shown at left.