Overview
This is a handy, low power Raspberry Pi HAT which features multi communication functionalities: GSM, GPRS, and Bluetooth.
It allows your Pi to easily send messages, connect to wireless Internet, transfer data via Bluetooth, and so on.

Features
Standard Raspberry Pi 40PIN GPIO extension header, compatible with Raspberry Pi Zero/Zero W/Zero WH/2B/3B/3B+/4B and later versions, Jetson Nano
Supports SMS, GPRS, DTMF, HTTP, FTP, MMS, email, etc.
Bluetooth 3.0, supports data transferring through Bluetooth
UART interface, for connecting host control boards like Arduino/STM32
Onboard voltage level translator, 3.3V by default, switch to 5V via jumper
2x LEDs for indicating the module working status
SIM card slot for 1.8V/3V SIM card
Baudrate auto detection (1200bps ~115200bps)
Control via AT commands (3GPP TS 27.007, 27.005, and SIMCOM enhanced AT Commands)
Supports SIM application toolkit: GSM 11.14 Release 99
Comes with development resources and manual (examples for Raspberry Pi/Jetson Nano/Arduino/STM32)

Package Contains
SIM800C GSM/GPRS HAT x1
GSM Antenna x1
Bluetooth Antenna x1
USB type A plug to micro plug cable x1
RPi screws pack (2pcs) x1

For more details you need to know, pls firstly send me message via Amazon, I will then send attached link including User Guide for you, thank you for patience.;D