There are only 20 IO ports in Arduino control boards, if we add some sensors, SD card, relay module and so on, IO port will not be enough. Image when you want to drive the LCD 1602 but without enough IO ports, how terrible? You can save 5 IO ports with this module, and it is compatible with Arduino.
Features
Compatible with Arduino 4 line control module.
You can use the Arduino official Library forectly.
With backlights and contrast regulator potentiometers.