Paraben's Wireless StrongHold Bag is a signal-blocking evidence bag for any type of wireless device. First responders can use this bag to ensure proper wireless procedures are kept and that the evidence is protected from potential case killers - after seizure wireless communications. These wireless communications can contaminate evidence and have even been considered wire taps when voice call data is recorded on cell phones after seizure. The special tri-weave material used in the Wireless StrongHold Bag is made of a nickel and copper woven fabric. This fabric is key in preventing unwanted signals from destroying evidence. Each bag comes with in its own evidence handling bag for proper evidence tracking.