Trust your important records to these acid-free polypropylene envelopes. The contents are clearly visible for quick reference. Great for document storage and inter-department use. Hook and loop closure secures 8 1/2 x 11 documents in place. Durable enough to use again and again, making them very cost-effective. Seam Type: Weld; Flap Type: Round; Security Tinted: No; Opening: Open Side.