Simply slide the innovative zip closure to effortlessly open and gain access or close and protectively seal this Zip Closure Poly Envelope. Contents are protected with a dust resistant and water resistant seal unmatched by traditional paper and poly envelopes. Black and silver colors provide opaque protection to keep materials out of sight and free from light. Clear front pocket allows easy, see-through identification of contents as listed on a cover sheet or routing slip. Envelope is made of durable, archival safe polypropylene.