Columbian CO397 10x13-Inch Clasp Gray Kraft Envelopes, 100 Count A durable MULTI-PURPOSE envelope. Dual purpose seal allows for multiple uses. Use the moisture activated gummed seal for mailing or the strong metal clasp for repeated use and storage purposes. Heavy-duty opaque 28lb gray kraft material provides privacy of contents. Open end closure. 10" x 13" 100 envelopes