Florence 4C mailboxes are USPS Approved and meet or exceed STD-4C requirements for new construction and major renovations. They are also ideal for private delivery applications. With numerous pre-configured 4C modules available; be sure to refer to USPS Approval guidance in product details below when selecting pre-configured 4C mailboxes for your project. This 4C module is not approved for Postal delivery as it cannot be mounted to adhere to all USPS installation regulations.