Jumbo Catalog Mailers are made with extra-durable, 18 lb. DuPont Tyvek which is strong enough to withstand the grueling conditions. Material resists punctures, tears and moisture yet is lightweight to save on shipping costs. 18" x 23" jumbo envelopes feature an easy, Flap-Stik closure which requires no moisture for a secure seal. Release strip allows you to quickly and easily open. Whether you're sending blueprints, art boards, large documents or reselling items on an online marketplace. These catalog mailers are an efficient, cost-effective way to make sure your items arrive intact.Jumbo Catalog Mailers are made with extra-durable, 18 lb. DuPont Tyvek which is strong enough to withstand the grueling conditions. Material resists punctures, tears and moisture yet is lightweight to save on shipping costs. 18" x 23" jumbo envelopes feature an easy, Flap-Stik closure which requires no moisture for a secure seal. Release strip allows you to quickly and easily open. Whether you're sending blueprints, art boards, large documents or reselling items on an online marketplace. These catalog mailers are an efficient, cost-effective way to make sure your items arrive intact.