The Viessmann thermistor decreases the current resistance in a manner that is inversely proportional to the temperature of the thermistor. The electronic control sends a current to the thermistor and can tell whether there is an increase or decrease in heat.
Comes with clip
Technical specification
Waist Sizeaa25ci13gvTypeSensorERP RatingNot ApplicableSupplier Part Number7819967Brand NameViessmann