Hossen&reg; Mini GPS Gprs GSM Tracker Car Vehicle SMS Real Time Network Monitor Tracking SIM card choice, terminal need to insert a GSM SIM card, SIM card choice pls refer to the dealer's opinion SIM card installation, use a hand to uncover the terminal cover, uncover SIM card slot cover, the SIM card metal face down into the SIM card slot, then fasten card slot cover, and finally put on the back shell GSM: 900/1800MHz or 850/ 1900MHz Voltage range: DC 9-38V Dimension(L*W*H): 2.2*1.4*0.04 inch / 55*35*1mm