Specifications Operating Voltage Range: 9 to 32 VDC Volts Alarm Current: ≤50 mA @ 24 VDC Strobe Flash Rate: ≤ 0.5S Alarm Sound Intensity: Minimum 100dB Operating Humidity Range: 10% to 93% Relative Humidity, Non-condensing. Description The Sound Strobe of notification appliances offers a wide range of Sound/strobes, for wall and ceiling applications, indoors and outdoors. They are designed to be used in 24 volt DC systems.