Postpak envelopes have been designed to fit standard Royal Mail post sizes. They have been labelled with the appropriate price band to ensure you don't pay more than you ought. Smart and professional-looking, these Size 3 envelopes are lined with bubble wrap so damage from being bumped around in the postbag is lessened. The outside is designed to resist tearing, meaning you can rely on these packets to stop your precious items being ripped, bent or damaged.