Poly Mailer 100 Mailing Bags Plastic Mail Envelope for Shipping 2.5 Mil Postal Bags (White, 12 x 15.5 inch) Lip Size: 1.5 +/- . 2.5-millimeter thickness (+/- 5%). Usable Dimensions: 12 x 15.5. Paper Liner: Clear with antistat. Adhesive: Synthetic rubber  Hotmelt,  minimum +/- 1/8.