Buzzers / Piezo buzzers / Piezoelectric buzzers / Microphones / cellphone speakers Application:

Buzzers serve as prompts or alarms, depending on the design and use, and can send out music, whistles, hums, alarms, electric bells, etc.
Buzzers are devices that can convert electrical signals into sound signals. They are used primarily in household appliances, bank systems, security alarm system, and also widely used in electronic toys, and games consoles.