Office Depot Lift & Press #9 White Double Window Envelope Pack Of 500, lift & press closure provides a permanent seal immediately upon contact, so you can be sure that your documents will safely arrive at their destination and you can easily see addresses with these double-window envelopes. Tamper evident seal provides added protection, there's no need to write out labels. Windows display the return and mailing address and are security-tinted inside for privacy and confidentiality.