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. Parcel lockers must meet a minimum compartment height of 15 inches. If the total number of parcel lockers in the mailbox installation exceeds the 1:5 ratio requirement; smaller parcel lockers may also be included.