Features: brand new and high quality TTL serial port for serial port, you can link directly to the microcontroller. Power module automatically boot, homing-networks. Onboard signal lights all the way. It flashes slowly when thereis a signal, it flashes quickly when thereis no signal. Supports quad-band GSM/GPRS networks, available for GPRS and message data remote transmission. The board features compact size and low current consumption. Specifications: Material:ABS Size:Approx.25x23mm/0.98x0.9inches Note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1 Set SIM800L Module