N95 Respirator Mask

How many layers does this KN95 mask have? Generally, it has 5 layers, including two layers of non-woven fabric, two layers of melt-blown fabric, and one layer of hot air cotton, effectively blocking particles and droplets.
What's the difference between KN95 and N95? KN95 is the Chinese standard, while N95 is the American standard. Both have a filtration efficiency of ≥95% for non-oily particles, and their protection levels are similar.
Can it be reused? It is recommended to use it once; if used intermittently for a short period, it can be worn repeatedly for a short time as long as it is not damp, not damaged, and has no obvious contamination. Once the mask gets wet, damaged, or contaminated, please replace it immediately.