Smooth white All Board Envelopes, squarely proportioned to 249mm x 249mm dimensions so they can conform with Royal Mail’s Postage in Proportion guide. They are produced from premium grade 500 micron, 350gsm, GD2 fully coated chipboard and include an easy-to-use peel and seal strip on a pre-folded flap. You can trust these board envelopes to protect paper, card and slim items during transit and they’re perfect for busy despatch operations as closing them is fast and easy. You can print directly onto the coated surface, and adhesive labels will also stick firmly.