SIM868 GSM/GPRS/GNSS/Bluetooth HAT for Raspberry Pi This is a plate , low power Raspberry Pi HAT which features multi communication functionalities: GSM, GPRS, GNSS and Bluetooth. It allows your Pi to easily make a telephone call, send messages, connect to wireless Internet, global position, transfer data via Bluetooth, and so on. https://www.waveshare.com/gsm-gprs-gnss-hat.htm