SIM800A Wireless Extension Module SMS GSM GPRS STM32 Development Board
 Size: 80*50*8mm
Voltage: 5V-18V
Serial communication
TTL serial port and RS232 serial port, TTL serial port compatible with 51, SIM32, ARDUINO and so on
Reserved voice interface, you can directly access mic, headphones and other equipment
Package includes:
1 x SIM800A Wireless Extension Module
1 x Antenna