Just thin cloth
I specifically purchased this to wear over an N95 mask.  There is no way I would use this on its own. Its the same type of material as most of my T shirts. You can see through it if you hold it up to the light.<br /><br />I took a picture of this next to a standard disposable mask and a 3M N95 mask as well as a picture of it stretched over an N95.  It doesn't cover it completly and requires it to be stretched a bit but it works alright and the wrap over your ears is slightly more comfortable than elastic.<br /><br />The sowing of the seems is well done and the material is about the same as a good t shirt.  So far they are working ok. I would like them slightly bigger but they work and seem well made.
Rating: 4 stars