... GSMFrequency channel850MHz/900 MHz /1800MHz /1900MHzGPRSClass 12,TCP/IP build in GSM MODULEGPS sensitivity-159dBmGPS positioning accuracy(2D RM)10 mGSM ... national 3E, explosion-proof, CE, ROHS certified2,Dual built-in antenna design, waterproof ,dustproof anti-corrosion and anti-interference3,Support ... lock the vehicle/car, just such as put the car in your pocket, Anti theft and do not worried steal . ...