This Indoor siren that simply plugs in to a mains socket. The siren also has a internal battery so intruders or burglar cannot simply pull it out the socket to stop it activating. This indoor mini strobe siren can be added to any G5 and A11 Alarm System to boost the sound output or to distract an indoor or burglar away from the control panel. Ideal for use in areas of your property up to 40 metres away from the Control Panel, for instant audible and visual notification of an alarm event. The strobe siren has a built-in rechargeable backup battery in the event of power failure.