"D1D9 Home Alarm System Wireless Built in Antenna Scare Burglar Away for DIY GSM House Security SCARE BURGLAR AWAY When someone trigger this alarm system that will be alarm to scare thief away and also will make a phone or sending a message to someone which you save the phone ..."D1D9 Home Alarm System Wireless Built in Antenna Scare Burglar Away for DIY GSM House Security SCARE BURGLAR AWAY When someone trigger this alarm system that will be alarm to scare thief away and also will make a phone or sending a message to someone which you save the phone number on the main unit.( No chime,No Wifi,Only support 2G T-mobile SIM card) BUILT-IN BATTERY This system work well when someone cut wires or power off. You don’t worry other people intrude your house when power off CELLPHONE FUNCTION This main unit can make the phones like a cellphone(Work with T-Mobile Card,SIM card isn't including) EMERGENCY HELP You can press an alarm button on the remote control when some emergency thing happen, this system will go off right now and will make a phone. REMOTE CONTROL You can control this gsm alarm system Arm/Disarm/Voice Monitoring /Intercom by cellphone anywhere "