These Survivor envelopes expand to provide lightweight, inexpensive shipping for bulky items. Expandable envelopes are made of puncture, tear and moisture-resistant DuPont Tyvek material. Envelopes made with Tyvek are half the weight of heavy duty paper envelopes, so you save on postage with each mailing. Our tough expandable mailers resist overstuffing, bad weather and rough handling to deliver your contents intact. With easy to use Quality Park Redi-Strip envelope closures, just peel and press for an instant seal. Heavyweight 18 lb Tyvek. Seam Type: Center; Flap Type: Square; Trade Size: #13 1/2; Security Tinted: No.

Features

• Expandable fit made of rip and water resistant Tyvek material with self seal flap.
• Strong, lightweight envelopes made of Tyvek material are half the weight of heavy-duty paper envelopes; save on postage with every mailing.
• Envelopes made with Tyvek repel water and resist acids, bases, salts, rot, mildew and stains; perfect for storing taxes and essential papers in the home office.
• Redi-Strip envelopes seal tight to keep contents safe-just pull and press-adheres without moisture for a clean, instant seal.
• Ideal shipping envelopes for clothing, books, binders and big bulky papers.