Office Depot Lift & Window #10 White Security Envelope Pack Of 500, self-seal envelopes with a tamper evident seal provide added protection. Security tinted inside for privacy and confidentiality. Made of crisp 24 lb white wove for a substantial feel. Forest Stewardship Council (FSC) for wood/paper products from forests certified to the 'gold' standard of responsible forestry. Forest Stewardship Council US-0081. FSC Certification ensures responsible use of forest resources and provides assurance that the fiber in this paper comes from forests that are well managed to protect biodiversity and the livelihoods of the people that depend on those forests. Greener choice contains 100% total recycled content.