With external measurements of 353mm x 518mm Rigid All Board Envelopes CP 010.08 are ideally sized for A3 items keeping them flat and protected in the post. The pre-creased envelopes allow you to adapt the depth of each envelope to best match the contents. At maximum capacity the internal size measures 340mm x 500mm x 50mm*. Customising for a snug fit gives better protection and avoids the need for fillers, making these envelopes fast to pack and minimizing postage costs. Smart and professional looking Rigid All Board Envelopes are manufactured in robust brown E-flute corrugated cardboard. They are designed to be resistant to bending with extra strong corners and edges to protect against bumps and crushing. They are also very secure being easy to seal with an integrated tamper-proof permanent adhesive strip. Customers have the benefit of an easy-open tear strip to make it simple for them to access their goods and the cardboard used complies with US safety standards to avoid the risk of annoying paper cuts. *Effective size decreases with increasing thickness