cabin filter (2 pieces) for all W124 with air conditioning.
The exchange of the cabin filter ist often forgotten, because the filter is hidden under the plastic grill above the fan motor. You can notice a blocked cabin filter, when the front screen gets steamed up, as the dirt in the filter binds moisture (s. example picture).
Apart from hygienic aspects, it is recommended to change the cabin filter annually, to keep an optimal view.
The package contains 2 pieces, both are needed.