This Wireless Doorbell from Dakota Alert is an easy, do-it-yourself wireless doorbell unit that comes with a base unit and one push button. The base unit has four LED indicators to differentiate between each of up to four push buttons (available separately). You can select a different tune for each push button out of the included 16 built-in tunes. When a push button is pressed, the flasher and corresponding LED will light up and the selected tune will play through the base unit's built-in speaker. Functions can be accessed and adjusted by flipping the cover open on the front of the base unit. The base unit is powered by three C cell batteries (available separately) and the push button is powered by the included CR-2032 battery.