18mm Speaker: 4 Ohm, 2.0 W

via Pololu
$14.40
SKU PL-1258

This compact, general-purpose speaker is great for adding loud, high-fidelity sound that can bring your project to life (or to annoy your friends and family with loud sirens and squawks!). If you have an adequate driver for it, such as a small MOSFET controlled from a microcontroller PWM line, you can really get much more volume and richness than you can from similar-sized low-power speakers and buzzers.

The speaker’s specifications can be found in its datasheet (1MB pdf).

18mm speaker with US quarter for size reference.

Bottom view of the 18mm speaker.

Frequency response curve for the 18mm speaker.

18mm speaker dimensions (in mm).