Difficult to assess smoke detector before a fire! Seriously, nothing simpler than to put the 9V battery and attach it to a suitable location as advised in the instructions. A red light flashes to check that the system is operational. A test button to check that the siren operates. It is powerful enough to break your ears and alert throughout the house during the test so you wake up. A pause button, called Hush will disable the siren in case of false alarm: for example, if your detector is in a kitchen and your cooking smoke a little. Rest assured, after ten minutes the detection resets automatically: no risk of forgetting and being unprotected. An alarm warns of low battery but it was not until the check that the 9V battery is worn out. In short, the product of a great brand, not too expensive, easy to install with the guidance provided. I recommend
