you can choose up to 2 of the following Gas sensors to be included to suit your application.
CO = carbon monoxide, (engine exhausts, wood & gas burning heaters)
CO2 = carbon dioxide, (we breath this out, if CO2 increased more fresh air is needed)
NO2 = Nitrogen dioxide, (diesel engine exhausts)
CH4 = methane,
C3H8 = propane,
H2 = Hydrogen Sulphide,
A = Ammonia,
Z = Ozone,
R22, R134A, R410A, R404A, R407C = refrigerant gases