This GSM ID card (box) size is the same as ID card. The frequency is 850/900/1800/1900 Mhz so can work for all countries. The sim card slot only support micro sim card. The transmitter range from GSM card to earpiece is around 40-50cm, depends on which earpiece you use. Build-in high sensitive microphone. The inside indicator can show the on/off and battery power (when charging, the indicator will blink). When you charging this device, pls make sure turn on it, then can be charged! Learn More
