12″ x 9″ x 4″ Deluxe Literature Mailer, White, 5/Pack (55884) | Staples Best

Thedeluxe literature mailer offers maximum protection for sending your most important documents. Each box assembles in seconds and is made of a strong corrugated materials, making it both efficient and effective. The mailer is a spacious 12″ by 9″, so most documents will fit comfortably. It is sturdy enough to hold hardcover books and other heavy items. When not in use, these mailers store flat to save space.