From Faraday Defense:
XL Non-window Faraday Bag offers Anti-tracking & Anti-spying. High Quality Blocking Material and Quality, Precision Stitching allow for Cell Signal, GPS, Rfid and WifI Signal Blocking. See other listings for additional variations and sizes of privacy bags. Fits all major cell phone makes and models as well as majority of latest external hard drives and tablets.
"Our best designed bag for performance. Double fold over Velcro closure ensures no escape and no penetration of signal. Sure to block signal with double layer of CYBER Faraday Fabric this bag is built for performance. Quality stitching with attention to detail you have come to trust with Faraday Defense’s canvas forensic Faraday bags. Faraday Bag offers Anti-tracking & Anti-spying. Applications: Cell Signal, GPS, Rfid and WifI Signal Blocker Pouch Case Bag Handset Function Bag. Great for protecting Tablets, Cell Phones, Passport, Credit Cards, External Hard Drives. Offered in Black Heavy Duty Canvas Exterior with CYBER Faraday Fabric security textile interior." -Faraday Defense