This is a small 12mm round active buzzer. It has additional circuitry in it which makes it easier to use but limits the buzzer to only making one type of a sound (tone). It only requires DC power source for the tone to be generated.
This buzzer will switched on by a 3-5V DC voltage. No other circuitry or PWM signal is needed, just DC voltage.
Note: This active buzzer cannot be used to play melodies.