It's more about hype than actual fact. Typical oil filters using paper or synthetic media have pores in the material that vary in size fairly widely. Do some internet research on exactly how oil filters are rated, it's not a simple cut and dried thing where the filter must stop all X micron particles in order to be called an X micron filter.
Btw, those "surgical metal mesh" filters tend to have more precisely sized pores, and tend to be around 30 microns. They do less filtering and flow more oil, leading to the performance improvement claims of the folks selling them. Less resistance to flow means less power required to pump the oil through the system. Not necessarily a good thing for a street engine you want to last a long time. The average paper or synthetic media filters these days run between 10 and 20 microns (rating). Very few I've come across claim to be 5 micron filters. Of course they can claim whatever they want, it's not like some all powerful government agency actually checks those claims for accuracy.
JMHO - Jerry
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Topic: 5 micron oil filter (Read 1078 times)