Fence or Gate Mount Mailbox Mounting Bracket (Unpainted Aluminum) Bracket Kit for mounting mailbox to wrought iron or chain link fence. You drill the holes so it fits your particular size of mailbox or e-mail us and ask us to drill the holes for you. Simple and easy to use. The bar is made of 1" x 14" x " aluminum. It clamps almost all brands of wall mailboxes to a fence or gate. You drill the holes so it fits your particular size of mailbox or e-mail us and ask us to drill the holes for you.