The coupling has a lens and a transparent cover disc with a heating element to prevent condensation or ice formation on it. The heater is a PTC resistor supplied at a constant voltage and of such a size that it also creates no heat damage to the coupling components. The part of the coupling that is heated has greater thermal conductivity than the rest of the coupling components and that part may be detachable from the rest, or might not be. Between the lens and the cover disc is a hollow space and the heater is one side of this. Its thermal connection to the cover disc is better than to the rest of the components.
