Overview The Apollo 45681-330APO sounder visual indicator base is a loop-powered sounder and visual indicator combined with a standard Intelligent Mounting Base. Compatible with XP95 and Discovery protocol it is used to signal a fire alarm in enclosed areas. Features Apollo 45681-330APO Two volume ranges 55-75dB(A) and 75-91dB(A) Visual indicator flash rate of once per second Synchronisation of 'alert' and 'evacuate' tones Synchronisation of visual indicator flash Individual and group addressing Unique acoustic and visual indicator self-test Built-in Isolator