4C Standard Mailboxes are constructed of heavy gauge aluminum with stainless steel components for maximum durability both indoors and out with a shelter. This high-security unit also includes one parcel locker for easy delivery and storage of larger parcels. The corrosion-resistant, weatherproof powdercoat finish protects the units from the elements, while the riveted shelves and concealed hinges limit pry points for added security. The carrier access door provides easy access for Postal Letter Carriers to release the master loading doors.