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 is green up to 1.000 ppm The traffic light is yellow from 1.000 ppm to 2.000 ppm The traffic light is red from 2.000 ppm to 3.000 ppm The traffic light flashes red from 3.000 ppm