16x2 LCD connector with potentiometer
The connector board operates on 5v current, either provided by the Raspberry PI or any other power source - as long as it provies clean 5v.
It features an on/off switch for the board and thus the LCD. It also features two potentiometers, one to adjust the LCD backlight and the other to adjust the LCD contrast.
Finally it comes with a a little push button, with which you can send a simple commands to the raspberry PI. You will need a script to watch for the push button event, of course, but there is plenty on tutorials on that on the net.
The purpose of the board is easy connection of an 16x2 LCD to the RPi without blocking all of the GPIO ports, like so many adapter cable hookups do. Instead you can just connect 1 5v, 1 GND and the usual 6 data pins and be done with it. The board is labelled so you can easily connect it.