Originally Posted by CDTraveler

Unfortunately masks made from knit fabric get very poor safety ratings. Stretchy knit fabric is very porous compared to woven fabrics.

A friend of mine did a lot of research on fabric and design before starting up a small business. She makes woven fabric masks with toggle fastenings that are really comfortable. I can personally recommend them - I own 5 of them now. She posts her masks on twitter as @AbingtonLions