Black Hole Faraday Bag - RF Signal Isolation for Forensics, Large Window Size - Signal Blocking, Anti-tracking, Anti-spying, Radiation protection for Cell Phones, Key Fobs and Credit Cards Forensic faraday bag designed for law enforcement digital forensics and military cell phone exploitation Large size bag: Put cell phones, GPS or tablets inside to block cell signals, satellite, Wifi, and bluetooth frequencies Shielded window allows preview of device inside to determine battery life, device state, and confirm signal isolation Proprietary ISOTech faraday fabric provides best in the industry signal shielding, you won't find better! Radio frequency shielding spec: 69+ dB attenuation (final bag spec, not just base materials spec)