The masks that were widely available at pharmacies, big-box stores and home improvement stores – until a worried public bought them all – works well at filtering out large particles like dust. See the chart below, which type of mask filters out 95% of virus.
The size of COVID-19 is between 80-160 nM, that's invisible to the naked eye and would easily pass through the unapproved face covering.
If you don't wear the mask properly, don't remove it properly or put it in your pocket and reuse it later, even the best mask won't do you any good.
Finally,
Better is to maintain social distance, washing of hands and should only wear mask if you have a cough or are recovering from COVID-19.
This is excellent advice and relevant to the current arguments about whether or not to wear a mask.