Count on JAM Paper® Heavy Duty Tyvek® Open End Catalog Envelopes to deliver your mail in style. Not only are these silver sturdy envelopes unique, but they are guaranteed to keep magazines, marketing materials, photographs, and more safe as they are tear and water-resistant. This pack contains 25 silver Tyvek® envelopes. Each envelope measures 11 1/2" x 14 1/2", 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.