Lang - Magnetic, All-Weather, Standard-Size - Mailbox Cover - St. Patrick's Day, Exclusive Artwork by Joy Hall Exclusive Artwork by Joy Hall Magnetic, all-weather vinyl, attaches securely to metal mailboxes. Includes magnetic adapter strip for wood and plastic mailboxes. Fits standard-size, rounded mailboxes, approx. 9"h. Mailbox cover dimensions: 17.75" x 20.75"