GPS and Mobile phone quad-band signal jammer for worldwide use. How Does it work? The cellphone jammer transmits low power radio signals to cut Off communications between cell phones and cell base stations. It does not Interfere with anything other than mobile phones within the 20 meter working Radius. Upon activating (turning on) the signal jammer, all the nearby phones Will indicate "NO NETWORK", so you can conduct your company presentation, Meeting, dinner, worship service, legal proceedings, or other important Activities without being disturbed. When the phone jammer is turned from on To off, all cell hand phones will automatically re-establish communications And provide full service. Specifications: Main function: Shielding cell phone signal within security radius Isolating Signal Bandwidth: - CDMA/GSM: 850-960MHZ - GSM (PHS)/CDMA1900: 1805-1990MHZ - GPS: 1500-1600MHZ Coverage Area: Up to 20 meters Power Source: Wall plug, car adapter, or built-in battery Internal Battery: 2000mAh rechargeable li-ion Typical Battery Life: 120 minutes Dimensions: - Antennas off = 112mm x 60mm x 30mm (L x W x D) - Antennas on = 195mm x 60mm x 30mm (L x W x D) Package Contents: 1 x High Powered GPS Cellphone Jamming Mobile Phone Signal Jammer 1 x Power Adapter 1 x Car Power Adapter 1 x English manual.