I have bought 6 of these. They only thing I need from them is CO2 measurements. 2 of them started to show fake data after using for half a year. Finally got my hands on tearing down one of them. The legend says in all reviews that it contains SenseAir S8 chip, don’t you believe it 
I don’t see any model or brand but form is not S8 that is for sure. Just sharing my finding.
