Breathable and adjustable. I wear these at my job in the Emergency Room; they have held up well so far. I was breathing heavy through the surgical masks and N-95s provided by my workplace. This KF94 was much lighter, easier to breathe through, and I feel less tired at the end of each shift.
Bluna face masks are comfortable and they do the trick of protecting us. KN95 and N95 masks fit too tightly, and they make it hard for me to breathe. I believe the ease of breathing with this KF94 mask is due to the large air space of the Bluna mask.