The circuit board is designed to play 17 different tones. Ding Dong, Ding Ding or the Westminster Chimes as well as a number of short musical melodies. After selecting the tune you prefer, you can repeatedly recall the same tune when you touch the doorbell button. The circuit is self contained and runs on a small 2032 button battery. The unit can be hidden anywhere but will need to be hardwired to the doorbell buttons if you wish to use the separate button.