SCS Moisture Barrier Bags Dri-Shield 2700 are manufactured from a laminate of multiple layers of aluminized polyester and polyethylene. Polyester provides puncture resistance. Metal layers are intended to provide shielding of Electrostatic Discharge (ESD) and to help minimize the penetration of electric field. A stronger polyester layer helps to prevent sharp trays from puncturing the bag. NOTE: Many additional custom sizes are available. Please contact us for more information if your desired size is not listed. - This aluminized moisture barrier bag is designed to provide a static safe environment for sensitive electronic devices. The bags are heat sealable and suitable for vacuum packaging. Bags are printed with ESD and moisture warning symbols and a lot code for traceability. NOTE: Many additional custom sizes are available. Please contact us for more information if your desired size is not listed.