The Firehawk FHB10 optical smoke alarm is powered by a 10 year sealed lithium battery guaranteed to last the entire lifespan of the alarm, with an end of life warning that can be silenced for up to 10 hours should it occur during the night. For easy installation, the alarm is powered up automatically when fitted to the mounting plate and the large test and hush button, which is almost the entire face of the alarm, makes testing very simple. It features a unique x-profile optical chamber design for reliable detection and robust false alarm rejection. The separate mounting plate ensures automatic switching on/off of the battery upon installation or removal. The test button is conveniently located and the alarm is small and compact.