Fit is tested quantitatively, using a Porta Count Pro, or qualitatively, using the Bitrex test. We've validated both methods.

Measured using a TSI 8310A. Full test method requires aerosolizing small salt particles and blowing them through the filtration material at 85 L/min. We have tested a variety of surgical masks and cloth masks.

If a mask isn't comfortable, no one is going to wear it. Comfort isn't just about how it feels on your ears and nose, but also whether or not it's breathable.