very economical, as for durability, time will tell

It looks good. I haven't used it yet

half of the ones I got had a broken button for the test.

they are not worth it, they do not work

it is not activated with cigarette fog, what kind of smoke sensor is this?

Very good !!

As others have written, the description says it includes batteries but it comes without them

I order 6 smoke alarm detectors and they sent me 3 carbon monoxide detectors

! ! ! ! ! ! ! !

While the packaging says it contains batteries, it did not contain any

Very good for its price.