[qldbureau]

I have already asked to the others, info about their model of the MH-Z19, but I get no answer. This could be important, because there are two models of this CO2 sensor, mine is the first model, called only by MH-Z19, but there are also a newer model called MH-Z19B.

This is the unit I bought. Unfortunately I cannot read the label, as I did not realise I stuck it down in its test bed position over the label, with a blob of Blu-Tac, and now I found has largely dissolved the ink.
If I can fully trust the description, it should be the first version, not B.
My setup is indoors presently whilst I am gathering and setting up external enclosures.