Specifications: 

• Compatible with Arduino 51 STM32 AVR MCU
• Prototype expand
• The dual frequency 900/ 1800 MHz, GPRS multi-slot class
• 10/8,GPRS mobile
• station class B
• Power supply range: voltage is 4.6-5.2v; current is 1A or
• more(the current is very important)
• Low power consume: 1.5mA (sleep mode)
• Operating temperature range: -40 degrees C to +85 C
• Communication interface: The TTL level serial interface
• compatible 2.85/3.3/5V MCU
• Size:49*50mm

Software: 

• SSCOM, download link is https://drive.google.com/open?id=1mjwZdAiDUuHmoxn...
• Document link https://tinyurl.com/SIM800.
• What you will get: 1pcs sim800a board, 1pcs GSM antenna and 1pcs connector.
• Warranty: Life time warranty, any question please contact freely.