3 Mil Poly Mailers Envelopes Bags, 9x12-inch, Self Sealing Mailer, 500 Bags, White/Grey Lip Size: 1.5 +/- . 3-millimeter thickness (+/- 5%). Usable Dimensions: 9 x 12. Paper Liner: Clear with antistat. Adhesive: Synthetic rubber  Hotmelt,  minimum +/- 1/8.