Aico Radio Link+ Battery Optical Alarm is a battery-operated optical smoke alarm with RadioLINK that sees smoke. No electrical wiring is necessary for the detection of all household fire types. powered by a 10 year lithium battery (not replaceable) , which is built to survive longer than the alarm's useful life. On a single system, up to 12 alerts may be coupled, suitable for locations where false alerts from smoke alarms could occur. Aesthetic appeal and compactness When the temperature hits 580C, the built-in sounder will produce a minimum sound output of 85 dB at 3 m. When the temperature falls below this threshold, the device automatically resets, goes silent, and signals other Radio LINK devices connected to it to stop. The alarm is fitted with a large, easy-to-use test to facilitate frequent testing of the alarm. The test button can be used to silence nuisance alarms.