Looking for big book packaging or sheet music envelopes? The A4 is a cardboard envelope large mailer and is perfect for delivering clothing, big books, cookbooks, puzzles, paintings, arts & craft materials, posters, maps, calendars and lots of other big, flat items through the postal system. The Lil A4 large envelopes are made from stiff 450 gsm material with specially designed folds to provide impact protection around the edges, minimising the risk of impact damage. The envelope features our leading peel'n'seal / tear-strip system for easy sealing and opening.