- Power Failure Alarm: The siren will sound when the power supply is cut off and silent when the power restore; the warning could be muted by on/off switch.
- Working voltage:100 to 250V AC. The LED indicater can show power out / failure alarm and power condition.
- Sound level:120dB within 1 meter.
- Using Method: place the 9 V battery(not included) in the battery compartment according to the positive(+) and negative(-). Then connect the alarm with AC power and turn on the alarm switch.
- What you get? 2x power failure alarm