Honestly theu are n99 tested/rated (at least as they say)
Here is original link which i wanted to buy but forgot and now its pain in the ass to get then lol (and im not willing to pay more than 30$ for a mask like that, not talking about 150$ lol or evenmore when auction will end lol)
https://www.amazon.com/dp/B07RLLCJZF
I liked everything about them from first sight, they seem breatheable, hot weather friendly which is one if most important things for me, because of me being liver donor, i have to wear mask when at crowded places or close enviroments... + big comfort is straps at back, ear loops hurt ears after 30min+ wear of normal mask. But breathability is most important for me as long term mask wear makes me sweat on face like crazy lol...
+n99 and washable mask with changable filters which got lifespan of 2 days ot something if i remember right. Thats all i like about them... their reputation on amazon 4 stars from 2864 votes and so on...
P.s
This made me respect them a lot if they arent liars lol (hope they arent..)
Q: Will this mask protect me against the corona virus?
A: Thanks for your question.
The following four points I hope will help you.
First of all,Our filters tested at a world Renowned Microbiological Testing Facility in Salt Lake City.UT.USA .Test report from Nelson Labs shows that Bacterial Filtration Efficiency 99.4% .
Second,Also I thought you would like to know 90% of our masks inventory had been sent to Wuhan, China for free, and our masks are fighting the coronavirus with people in the disaster area. I'm sorry we can't meet your purchase needs at this time, because we will continue to support the supply of masks in the disaster area until the epidemic improves.
Third,No matter what brand of mask will only help provide protection if a full seal can be formed with the face.
Fourth,only wearing a face mask won't protect you from the coronavirus.It also includes get in the habit of washing your hands frequently,and wearing goggles , etc .