10" x 13" clasp envelopes - 28lb durable golden kraft - for file, storage, or mailing - 15 count pack desktop publishing supplies, inc. desktop publishing supplies, inc. brand clasp envelopes are great for everything from home and office use to school and business. clasp envelopes make it easy to file or store documents, letters, and much more. these clasp envelopes also feature a moisture activated gummed flap for sealing- great for security and for mailing purposes. made from a 28lb bond golden kraft paper that keeps your contents safe.