Raspberry Pi GSM adapter is used to connect Raspberry Pi GPIO and the GSM/GPRS Module. In addition, there is DC external power supply connector, plus a toggle switch, so you can either choose the raspberry pie internal power supply, or select an external one.
Compatible with GSM/GPRS Module
Switchable and strong external power supply
Communicate Raspberry Pi with GSM/GPRS Module
Connect with modules compatible with Raspberry Pi GPIO