Envelopes are made with a material that inhibits the growth of mold and mildew to protect your contents. 10" x 13" interoffice envelopes feature a string-and-button closure for convenient document routing. They are a must in any office, keeping documents contained and organized while routing throughout the office. 28 lb. white wove stock is durable enough for prolonged use. Security tint preserves confidentiality. String-and-button closure holds up over time and allows easy access. Five columns on both sides feature narrow ruling to fit signatures. They are hole-punched on both sides to provide a preview of contents without opening.