Rigid All Board Envelopes CP 010.03 are pre-creased to allow you to select a capacity of up to 50mm to better protect your items and save on postage costs with neatly fitted packaging. With a flat external size of 229mm x 310mm and internal dimensions of 215mm x 300mm x 50mm* the ABEPLUSR3 is perfect for sending all kinds of A4 items including frames, artwork, electronics and books that need to arrive in excellent condition. Rigid and resistant to bending these envelopes are made in robust brown E-flute corrugated cardboard. The edges and corners are reinforced offering extra protection for important flat items in these areas that are vulnerable to crumpling or crushing in transit. These adjustable Rigid All Board Envelopes present a smart, professional image and are convenient for customers to open with an easy-open strip giving quick access to the goods inside. *Effective size decreases with increasing thickness