50 x A4 Envelope Box - 350 x 240 x 20mm - Packaging Now
Tenzalopes™ Biodegradeable A4 Paper Wallets – Plain - Hub Packaging
Mailer Envelopes/Cardboard Envelopes A4 X 10/Pack - Rigid Mailer A4 for Book Packaging DVDs etc The Ideal Capacity Book Mailers Expand to Fit 35mm Thickness, Large Letter Size at 25mm. : Amazon.co.uk:
Cardboard Envelopes For Classroom Books & Sheet Music – Lil Packaging
C4 MATT METALLIC ORANGE PADDED ENVELOPES (324 x 230MM)