Pack of 2 SFM 27 SFM27 Buzzer 3V 24V Universal Electronic Buzzer Continuous Sound

Sepcifications

The SFM-27 is a widely popular, high-decibel active piezoelectric buzzer that operates on a wide DC voltage range. 
Because it is an active buzzer, it features an internal drive circuit meaning it produces a loud sound immediately when DC power is applied, without needing an external oscillator or complex programming.