JAM Paper® Tyvek Envelopes provide exceptionally durable protection for your mailed items!JAM Paper® Heavy Duty Tyvek® Open End Catalog Envelopes are an excellent choice for all your mailing needs. Whether you are sending marketing materials, catalogs, or artwork, these purple envelopes cater to it all. Contents stay safe and in one place as they are protected by water and tear-resistant envelopes. This pack contains 10 purple Tyvek® envelopes. Each envelope measures 10" x 13", has an open end opening (no clasp, gummed), straight flap, self adhesive strip closure, is made from 28 lb. paper, is 10% recycled, and has a smooth finish.