Quality Park® Survivor® Tamper Evident Catalog Mailers are made with durable 14 lb DuPont™ Tyvek®, which is strong enough to withstand the most grueling conditions. The material is puncture, tear and moisture resistant—virtually indestructible. Yet, it is still lightweight which can provide a savings on shipping costs. Each envelope has a unique tamper indicating panel that displays the word "OPENED" in red if the seal is broken. Catalog mailers made with DuPont™ Tyvek® material are lightweight, yet strong and durable. A unique tamper indicating panel on the envelope flap displays the word "OPENED" in red if the seal is broken. Made with DuPont™ Tyvek®, these mailers are tough enough to resist punctures, tears and moisture from the shipping process. Feature a Flap-Stik® peel and seal closure for a clean, sanitary seal without moisture and a release strip for quick opening. Country of Origin: United States