Breathability is an extremely important factor in a face mask's performance, which you can read about here. A mask that allows more air flow not only allows you to breathe more easily, it’s also crucial for any filtration effects. Knit fabrics are great for breathability because of their looped construction. Rather than forming a flat, compact wall like a woven fabric, the interlocked loops of our knit cotton create a complex and 3-dimensional pattern of yarns and pockets. This lets air flow through the mask while still helping provide coverage and absorb moisture.