This is a popular 20x4 LCD display made by JHD. It is based on the HD44870 display controller which makes it is easy to interface this LCD most microcontrollers. Its extreme popularity ensures that no matter which microcontroller platform you are using, you will definitely find ready libraries to use this LCD.
It works of 5V and has Green Backlight which can be switched on and off as desired. The contrast of the screen can also be controlled by varying the voltage at the contrast control pin(Pin 3).