Blake Purely Packaging C4 324 x 229 mm Board Back Pocket Peel & Seal Envelopes (13935/20) Manilla Pack of 20

Amazon

Sturdy and reliable, our board back envelopes keep documents flat and protected in transit, with ‘Do Not Bend’ printed for added security. Perfect for mailing certificates, photos, and important paperwork. Pack of 20 Qty. Sealing Type: Peel & Seal | Quick and easy sealing—no need for tape or moisture. Size: 324 x 229mm | Suitable for C4 uses. Model No. 13935/20

Zoro Tools

Heavy duty board back envelopes in white and manilla, made using 1000 micron backing board and a heavyweight face paper to ensure protection when posting bendable items.