Family celebration mailbox covers from Flagsrus for all occasions. Weddings, Anniversaries, Graduation, Births, Birthdays and more. Add a splash of color with a vinyl weather resistant mailbox cover! All covers feature a slot for the postal carrier alert flag. These covers attach to the mailbox with magnets. The standard size fits 6.5" x 19" mailboxes. No worry if you have a plastic or aluminium box, see the Adapter Kit.