Brown Kraft String/button Box-Style Interoffice Envelope, #97, Two-Sided Three-Column Format, 10 X 13, Brown Kraft, 100/box Keep all project documents together inside the large envelopes to help minimize confusion and error. Take advantage of the double-sided, preprinted box labels to note the envelope's entire lifecycle. String and button closures make it easy to insert, remove and view contents as needed. Tear-resistant, durable kraft paper is ideal for busy offices and protects confidential data.