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.. - Flaps Closed. - Outside Seams. - Peel and Seal. Box Quantity: 125. Pallet Quantity: 16,500. Features. Self-adhesive closure. Yes. Media weight. 120 g/m². Window. No. Product colour. Brown. Envelope format (ISO 269). C5 (162 x 229 mm). Weight & dimensions. Length. 162 mm. Width. 229 mm. General. Product family. Purely. Product series. Packaging