The F-filters collects the dust but even the best filter in the world could stand an overload.
Therefore all CP suction motors are equipped with a motor protection filter which protects the motor from any overload or leaks in the F-filters.
If there is any dust in the filter chamber when changing the F-filters you must also change the motor filter!
Features of the filters include:
High filtration degree
Environment - friendly
Download technical specifications here.