Samples of our masks were tested by engineers & rated better than some commercial brand medical use surgical masks. "As the person who has been donning all the masks, I really appreciated the comfort & adjustability of the ear loops. The finding that the nylon layer didn’t improve the particle removal percentage means that the mask fits well as designed, & the breathing air is passing through the mask rather than around it." Northeastern University. Please pick 1 color fabric for the outside of the cover. Washable! Fitted style and nose piece will help keep glasses from fogging up. 2 layers of cotton/polyester (liner fabric will vary). 1 layer sewn in Pellon 50 interfacing. I use soft stretch knit for adjustable with a knot on the ear loops. Know the efficiency of the face coverings you are wearing!