A strong and reliable mailing solution for sending important documents, certificates, photographs, prints and paperwork safely through the post. These C4 board backed envelopes are designed to fit A4 documents flat without folding, helping your items arrive neat, protected and professional. C4 / A4 size envelopes measuring 324mm x 229mm, ideal for standard A4 sheets without folding. Strong board backing helps protect contents from bending, creasing and folding during transit. Clearly printed in red to help postal and courier handlers identify your mail as protected document post. These 25 x C4/A4 hard backed manilla envelopes are perfect for mailing documents that need extra protection. The rigid board backing helps reduce bending, while the clear “Please Do Not Bend” warning gives you.