When you have a steel locking mailbox that is subjected to outdoor weather extremes, it is critical that the powder coat (see previous post) is of the correct thickness.
There is no way for an average homeowner to tell the thickness of the paint on a locking mailbox. This requires a special electronic tool that can measure the thickness. The thickness is measured in millimeters. The best way for an average homeowner to make sure the powder coat is the correct thickness is to buy a locking mailbox from a trusted source.