Post your products withour fear of damage in these brown solid board envelopes. The 450-550 gsm solid board gives the envelope structure & rigidity & protects against perforation & tearing. Perfect & simple sealing thanks to the peel-off self adhesive strip, eliminating the need for tape. Open the solid board envelopes easily after sealing with the handy tear-off strip. Each envelope is expandable up to 20 mm in height, making this product ideal for a range of postal uses. Use this solid board envelope for documents, files, DVDs, books, & for a variety of other flat items. Sold in packs.