16mm sound buzzer:(6V,12V,24V)top shape:round,square,rec can be used in AC/DC.16mm Flashing buzzer buzzerCoherent and imtermittent sounds could be made sperately from every different models. Technical data (UZ16 Series Buzzers) Rating Voltage6V AC/DC12V AC/DC24V AC/DCFrequency2.3+-0.5KHZSound output at 1m(dB)75 Life(H)1000 Dielectric Strength1000V Ambient Temperature-10°C~+55°C