Measure without disturbing cable: With the set, you take care of all relevant measurements in the ventilation duct and at the air/ceiling diffuser. You receive the testo 440 dP climatic meter incl. differential pressure sensor, two impeller probe heads (Ø 100 mm and Ø 16 mm) and a humidity/temperature probe head - all three of which can be plugged onto the universal Bluetooth handle supplied. For more convenient measurements, both impeller probe heads can be combined with the telescope included in the set. The equipment can be transported comfortably and safely in the robust case.