Rigid and durable Paperboard Mailers are the perfect choice for mailing items that should not be bent, like photos, important documents, calendars, paperback books, and CDs. These envelopes are made of stiff paperboard to protect the contents, and the paperboard is eco-friendly with 95% post-consumer content. Be confident that the materials will arrive intact with the extra strong Peel & Seel® closure. Recipients can easily open the paperboard mailer upon receipt with the pull strip similar to what you would find on overnight mailers. Paperboard Mailers come in a variety of sizes and are white on the outside.