Firex Mains Ionisation Smoke Alarm that can be interlinked with up to 23 other Kidde mains alarms, be they ionisation, optical or heat. Once interlinked, the detection of the relevant danger by an individual unit will sound across all the connected alarms. Ionisation alarms are for use in areas where there is danger from fast-flaming fires. This mains-powered unit complies with UK Building Regulations for new housing and associated standards (Grade D BS 5839, Part 6) and should be installed by a qualified electrician. It can be used throughout the home, except in the kitchen where a FIREX Heat Alarm is recommended.