The traditional shape of our Classic Curbside Mailbox is the only thing this mailbox has in common with a standard hardware store mailbox. The solid cast aluminum construction, with 20% thicker walls than our competitors, provides added strength and the powder coated finish will maintain a lifetime of beauty. The Main Street Mailbox Post features a 4? x 4″ square post with sculpted corners and accent flutes for a unique look. Made entirely of Aluminum with Stainless Steel components to eliminate rusting. Direct Burial installation required.