Compact design. Easy to high in pocket. Build-in rechargeable backup battery, over charge protection. Ideal for personal privacy protection use. A pocket/portable GPS jammer/blocker, which produced in our China factory. It's working on center frequency of 1575.42MHz, could helps you get far away from spy devices, which can be quickly installed and allow the users to track your every move using Google earth etc or a GPS recording system. Frequency: GPS L1 System (1450-1600MHz) Coverage: 5-15 Meters Radius Current: 200mA Power: 150mW Voltage: DC12V / AC220V Impedance: 50 Ω Battery Capacity: 1500 mAh (battery life is 2 hours)