Quality Park Open-end Envelope – Catalog – #1 [6″ X 9″] – 14 Lb – Peel & Seal – Tyvek – 100/box – White (R1320). Manufacturer Part Number R1320. Lightweight 14 lb Tyvek. Seam Type: Center; Flap Type: Square; Trade Size: 6 1/2; Security Tinted: No.