In the house I had been always 2 smoke detectors. Corridor below & above.
Since there is soon compulsory smoke detector zuhaben. I wanted to ever provide.
So ordered 6 smoke detectors, they were here Inexpensive and positive review.
Your size with Ø100mm XH 30mm makes them quite small and unscheibar. Unlike my two earlier.
The volume does not zuüberhören. So far everything clearly.
There's a star.
Unfortunately, these smoke detectors are useless.
After a month, the batteries supplied was empty.
All refurbished - 1 month ago later the same.
One can not say enough Batterin for these devices have since.
And it is precisely the false alarms.
So I now bought and expensive because everything is fine.
Zhudan Electronics Ei650-