Weather Tough, Year-Round: Rain, snow, or sun—galvanized steel construction makes this mail box one of the most reliable metal mailboxes for outside use. Rust-Resistant Finish: The black powder-coated surface adds an extra layer of protection to this curbside mailbox, helping prevent corrosion in all climates. Built to Fit it All: With it's oversized interior space, this extra large rural mailbox is designed to meet serious curbside mailbox delivery needs. USPS Post Master General Approved: Mailbox is USPS approved, as required for all curbside delivery by U.S. Mail carriers - for smooth, uninterrupted service.