180mm x 235mm - C5. 234mm x 334mm - C4. Sometimes known as "capacity book mailers", they can adapt to the thickness of the contents by up to 50mm - perfect for also posting DVDs. Artwork, computer games and brochures. Simply pop the item/s inside and close with the secure peel-and-seal strip.You can label or write directly on the smooth Manilla Kraft finish. And there is an easy tear-off opener. These kraft envelope-style flat mailers are ideal for sending out documents that range from invitations and photos to passports and financial statements. The perforated tabs at both sides of the flap make them easy to tear open, while the self-adhesive design tightly seals the envelope to keep your documents contained inside. The clean style of the rigid mailers give a professional look that is great for both business and personal use. Please Note: The colour of the product may vary based on the percentage of recycled material used in production. THANK YOU FOR SHOPPING WITH US AND WE HOPE TO SEE YOU AGAIN!