20 Brand New Tyvek® 10×13 Open End Envelopes with **FREE US SHIPPING** Only envelopes made of DuPont™ Tyvek® offer the unique combination of lightweight strength, versatility and excellent print quality. These 10×13 Tyvek® envelopes are made of a synthetic fiber called olefin which makes the envelope very strong. They are lighter than paper envelopes yet considerably stronger. They are water, moisture, rip, tear and puncture-resistant These envelopes are made of standard 14 lb. Tyvek and very lightweight at about 3/8 ounces each. The opening is on the side that is 10″ (also known as open end). These are also easy to close, as you just remove the plastic strip which covers the adhesive and then press it closed. These may be lightly folded when shipped. (This listing is for 20 envelopes even though the picture only shows 5. Though this item is typically sold in a box of 100, this listing is for 20 envelopes.) About the Seller: I ship really quickly and let you know when it’s going out. I am a TOP SELLER and have almost perfect feedback (99.9%). I don’t charge exorbitant shipping so that I can just show a lower price for the item. Thanks for looking and have a great day!!!