This SFM-27 active buzzer has quite a few decibels (more than 95dB!). This buzzer is mainly used in alarm systems since these buzzers make a deafening noise attracting all attention. This buzzer is suitable for 12V, but can handle a voltage between 3V and 24V. Since this buzzer generates its own frequency (3000 Hz), iyou will only need to connect power to activate the alarm.