Which Buzzer?

Hi,

I am making a standalone Arduino project powered from a 3.7V lipo battery (3.5-4.2V range).

I am trying to find a buzzer that can work well with the 3.7V lipo battery. It needs to be clear, loud and have good range. It will be turned on an off using a 2n22222 transistor.

Can anyone recommend a particular buzzer?

You could buy many buzzers, and still have a louder sound with a piezo element or speaker.
What is loud ? How much power is allowed to draw from the battery ?

A piezo element with the louder toneAC library and a good housing for the piezo to make it louder might be a good option.
http://playground.arduino.cc/Code/ToneAC

Thanks for your response.

What is loud ? How much power is allowed to draw from the battery ?

I need to be able to hear it through a plastic enclosure. It will be used as an alert mechanism. The maximum current would be about 20mA from the battery.

I am after a complete unit with maximum 10mm diameter.

Thanks for any suggestions