With this interface, you can connect an LCD screen while saving your digital pins, since it takes only 2 pins: A5 / A4 on a Arduino UNO and 20/21 on a mega. you have a small blue potentiometer to vary the contrast. Warning it is not compatible with the library Adafruit I had to use the library to find "new-LiquidCrystal" or. I bought at Hi-Elec for information but considering the price it would be a shame to pass!