CO2 measuring instrument with securely attached probe, batteries and calibration protocol.

Testo 535, the efficient CO2 measuring instrument for measuring indoor air quality. Bad air quality in rooms can lead to tiredness, lack of concentration and illness (Sick Building Syndrome) due to high CO2 concentration (greater than 1000 ppm).

  Repeated calibration is unnecessary
  Long-term monitoring
  Long-term monitoring with maximum and mean calculation
  Highly accurate, highly efficient
  Repeated calibration is unnecessary