Traffic light set for climate monitoring in enclosed spaces With this traffic light, the current carbon dioxide concentration in the ambient air can be measured and clearly displayed using the three traffic light colours. Completely assembled incl. stand and power supply unit, ready to use thanks to Plug & Play Can be wall-mounted with accessories (975.883.41) The traffic light lights up green up to 800 ppm The traffic light lights up yellow from 800 ppm to 1.200 ppm The traffic light lights up red from 1.200 ppm to 2.000 ppm The traffic light flashes red from 2.000 ppm