Happy Hours Hi-tech Real Time Smallest Portable Mini A8 GPS GSM/GPRS Tracker Global Security Tracking Monitoring Car Kids Pet Locator Device Tool Finder For Caravans Boats Motor Homes Trucks Vans & Construction Machinery Hot Power on: open the back cover, put the SIM card into the seats, then it is automatically power on. When booting, indicator will light for 10 seconds, after the indicator is off, cover the back cover then it can be used. Send 0000 SMS to turn off sound control function.Send 1111 SMS to turn on sound control function. SOS Emergency callEdit the content of messages capital lettersSOSto alarm, directly press the key SOS above three seconds after the success of seting, the alarm will directly call the seting number. And the indicator will flash. SOS Emergency callEdit the content of messages capital lettersSOSto alarm, directly press the key SOS above three seconds after the success of seting, the alarm will directly call the seting number. And the indicator will flash. When installing, please pay attention to GSM network signal strength, do not install in no signal or weak signal of place, so as not to affect the use effect.