How to block wireless signal - 3g signal blocker in history

How to block wireless signal,3g signal blocker in history,d_10px pad_l_28px big allborder"> Product Specifications: GPS and cell phone Jammer Isolating Signal Bandwidth GPS: 1580~1700Mhz CDMA: 850-894Mhz GSM: 935~960Mhz DCS: 1805~1880Mhz Typical Coverage:...