There are many reports of Chinese N95 masks being imported into the US that do not filter 95% of particles (as is required to be a *N95* mask) or are otherwise defective.
There is also a lot of suppliers of medical suppliers who have popped up recently that have shown themselves to be unreliable, at best.
I would strongly recommend against buying from anyone selling masks, medical supplies, or anything coronavirus related on this forum.
Seen this one on the Meta board topic
https://bitcointalk.org/index.php?topic=5245620.0 I think it's really better to avoid those sellers in this forum and instead buy surgical or non-surgical masks on trusted suppliers.