Oil contaminated compressed air used in tools or machines expands and escapes into the ambient air as oil vapour. The vapour creates an oil-film on surfaces which f.e. makes it difficult for paint or adhesives to settle on to this surface. Oil-vapour often carries health-hazardous nitrosamine. In general, the human olfactory system can detect oil-vapour at 0.3 mg/m³, the typical smell in workshops.

In contrast to filter elements with just a few layers of activated carbon cloth, the Clearpoint^® V cartridge is filled completely with activated carbon. The amount of activated carbon in the BEKO cartridge is twenty times as much as in the normal filter element types.

As the compressed air flows through the cartridge, it continually moves across activated carbon. The contact time of air and activated carbon is considerably longer than in a filter.

To assess the compressed air quality, an adapter with an oil check indicator and a manometer may be mounted on the head of the filter/absorber. When the needle valve is opened fully, a specific volumetric flow will pass through the detector tube. The oil residues in the compressed air cause the detector tube to turn red from the bottom upwards.