MAILERS4U 9 x 12 Inches Poly Mailers Self Sealing Shipping Envelope Bags - 2.4 Mil, Pack of 500 (9x12-PM-G60-500PK) 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!