JAM PAPER Tyvek Tear-Proof Open End Catalog Envelopes - 10 x 13 - Yellow - 10/Pack Color: Yellow Size: 10 x 13 inches Quantity: 10 per pack They've made this durable polymer composed of high-density polyethylene fibers, a synthetic material that is extremely hard to rip and tear. Tyvek is a registered trademark of DuPont These Tyvek envelopes offer a strong self adhesive strip and a more advanced tear and water resistant protection for your important papers and files