MAILERS4U 6 x 9 Inches Poly Mailers Self Sealing Shipping Envelope Bags - 2.4 Mil, Pack of 400 (6x9-PM-G60-400PK) Poly Self Sealing Privacy Mailer Envelopes Grey Outer Color & Black Inner Color Strong 2.4Mil Thickness Poly Lightweight, Durable, Professional, and Private! Self Sealing for Easy & Secure package!