4. CORRECTLY EVALUATE THE FILTER SURFACE
The dust filter is one of the most important organs for the smooth operation of the sweeper, so carefully examine the capacity of the filter surface and the quality of the filter material, whether in fabric or on paper.
Attention! If the filter is on “paper” consider the amount of folds and the distance between them. A “paper” filter with an upper filter surface, but if it is made up of so many very close folds, it is clogged earlier (the machine powders), compared to a lower filter surface, but with more distant folds (because the filter cleans better and has greater filtering autonomy.).