12v piezo buzzer:(6V,12V,24V) CE,ROHS cert top shape:round, ... can be used in AC/DC round and rectangular 12v piezo buzzerCoherent and imtermittent sounds could be made sperately from every ... AC/DC24V AC/DCFrequency2.3+-0.5KHZSound output at 1m(dB)75 Life(H)1000 Dielectric Strength1000V Ambient Temperature-10°C ...