This is another great IIC/I²C/TWI/SPI Serial Interface. As the pin resources of controller is limited, your project may be not able to use normal LCD shield after connected with a certain quantity of sensors or SD card. However, with this I²C interface module, you will be able to realize data display via only 2 wires. If you already has I²C devices in your project, this LCD module actually cost no more resources at all. It is fantastic for based project.