Catalog mailers are made with 14 lb. DuPont Tyvek that is strong enough to withstand the most grueling conditions. Durable material resists punctures, tears and moisture yet is lightweight to save on shipping costs. Envelopes expand up to 1-1/2″ for bulkier items such as books, large contracts and more. 10″ x 13″ white mailing envelopes feature an easy, Flap-Stik closure that requires no moisture for a secure seal. Release strip allows you to quickly and easily open. Whether your sending critical documents or reselling on an online marketplace. Survivor catalog mailers are an efficient, cost-effective way to make sure your items arrive intact.