All our book wraps contain 'peel & seal' strips with permanent strong adhesive for easy and efficient application and use. A pack of 25 x large C4 / A4 size book wraps, also known as cardboard mailers. The size of these quality wraps is 326x245mm (length x width), and the depth is adjustable between 0-70mm. Perfect for A4 size books, as well as slightly oversized A4 cook books, these are extremely high quality cardboard mailers manufactured in the UK. The C4 size of mailer represents a packet size for royal mail purposes. The weight of each mailer is 125g. They are the same mailers as used by Amazon for mailing out their books, and the original Bukwrap brand.