JAM PAPER Tyvek Tear-Proof Open End Catalog Envelopes - 10 x 13 - Assorted Colors - 25/Pack Assorted Tyvek Envelopes (Red, Blue, Green, Purple, and Black) Size: Open End (10 x 13 Inches) Quantity: 5 Envelopes per Color, 25 Envelopes per Pack Tyvek envelopes are very durable and much more tear resistant then regular paper envelopes. These envelopes are 10% recycled, have a commercial flap, and a semi-smooth textured finish. These envelopes are made out of the same Tyvek material that helps insulate houses, making them very durable! Use these for all of your important personal or business mailings, or around the home and office!