The one that I showed in post 12 has NDIR sensor and has never reset to 400. This unit appears rebranded by several companies, including InkBird, MOES and others.
My only gripe with it is that the battery sucks, so get one with a cord.
In any case, you can type "co2 detector NDIR" into amazon and find some units.
My only gripe with it is that the battery sucks, so get one with a cord.
In any case, you can type "co2 detector NDIR" into amazon and find some units.