Universal passive buzzer, resistors 16 ohms. Driven approach and works the same as with ordinary speakers.
Passive buzzer means need to add audio drive signal to make it sound.
Size: 12mm* 8.5mm
100 x Passive Buzzer AC 12MM*8.5MM 185 16R Resistance 3V 5V 12V In Common Use Packed Safely in Bubble Bag.