Arduino Piezo Buzzer
With the Arduino Piezo Buzzer and the right code, you can play a tune with your arduino
Rated Voltage: 3.5V
Operating Voltage: 3-5V
Sound Output: 85-95 dBA
Fast service, reasonable prices. The Piezo buzzer is not really a buzzer, it's more like a speaker. You have to apply a tone to it, not just a voltage. A DC voltage will only get you a single faint click. Not a big problem, but I first tried to use it by applying a DC voltage to it, which did not work.