Faraday Backpack offers 85 dB (400 MHz-4 GHz), Anti-tracking & Anti-spying. Applications: Cell Signal, GPS, RFID and Wi-fi Signal Blocking. Great for protecting Laptops, Tablets, Cell Phones, Passport, Credit Cards, External Hard Drives. Backpack is made with a durable black canvas exterior and lined with 2 layers of copper-nickel fabric. Inner Pockets block radiation and outside zipper pockets for convenient storage. Comfortable, adjustable shoulder straps and convenient mesh sides pockets complete this bag.