Rust-free Mailbox Mounting Bracket, Aluminum, Extra Large (Fits 23.5&rdquo; L x 11&rdquo; W mailboxes) PLEASE READ: Fits post-mount mailboxes sized 23.5 length x 11 width and posts of 4" - 6'' widths. Easy installation with pre-drilled holes; instructions included Made in the U.S.A. with mill finish and factory bent Rust-free aluminum; resists rot and rust Bulk discount pricing available for purchases of 50+ units. See Special Offers and Product Promotions for more details.