Description
Dunhill Blue Cap Crystal Filters for Slim Cigarette Holder
The Double Action Crystal filters:
These are made in Germany and designed to use both an impaction system (through the blue cap) followed by filtration through porous silica gel crystals further cleaning the smoke. The advantage of these two systems within a single filter is a significant increase in overall effectiveness; apparent as the white crystals change to dark brown – at which stage the filter should be replaced.
