As clearly shown in these photographs taken using a microscope,
the cotton filter (H&M) is made of extremely coarse yarns while
the polyester filter (SUPERCOMPETITION) is made of much finer
yarns sized to the micron.
Thanks to this special design, polyester fabrics guarantee
more efficient filtrationand excellent air permeability as all our
tests have shown.
Nonetheless it is to be pointed out that the results obtained by
testing cotton fabrics have not been 100% reproducible and this is
due to the weak and yielding texture of the cotton gauze.
However the following results are the best results we obtained.
As to polyester fabrics, results have always been 100%
reproducible and accurate