10" x 13" catalog envelopes are made of heavyweight, 28 lb. brown Kraft stock for home or office mailing, storing and organizing. They are a must for keeping projects, files and mailings manageable. Sturdy stock withstands extensive handling and mailing. Contents are protected during use to give you assurance they arrive unharmed. 10" x 13" size accommodates standard-size documents without folding. Redi-Seal closure saves time and creates a secure, permanent seal without requiring moisture.