We are concerned that many retailers are selling face masks that are made from loose, fabrics and synthetic fabrics that may cause reactions to the chemicals. You need tightly woven fabrics to meet the current recommendations. 
We make our masks with 3 layers of organic 250 or higher thread count sateen. This higher count is breathable but tight weave to prevent droplets from leaving your face. Tested with a candle for effectiveness. 
These highly effective somewhat breathable masks are meant to be secured with their natural elastic comfort straps and can prevent that mask irritation that occurs with most elastic. Ideally you want your mask to fit snugly, so we offer 8 sizes.
Measure from top of left ear where it meets head in front across bridge of nose to other ear where it meets head. See diagram for your best fit. The soft cotton covered elastic stretches for a better fit. 
Machine wash dry, or spray with hand sanitizer. See our hand sanitizer here. 
XXL 12.5-13" Men (my hubby wears this size)
XL 12-12.5" Men
L 11.5-12" Men and some women
M 11-11.5" Women
S 10.5-11" Small women and teen
XS 10-10.5" Child/teen
XXS 9.5-10 Child
XXXS 9-9.5 2-6 year olds