This smoke alarm came recommended by the professionals. It was easy to instal including the pairing of the alarms. There however seems to be a design fault in that the on/off switch inside the unit is fragile and on two of mine fell off. As the units are sealed they cannot be repaired. Clipsal customer care and their tech guys were very helpful but the end result was that the two broken units were replaced within 3 days by their local agent who installed and tested the entire setup. Overall a shaky start but hopefully no more problems.