The outer layer (waterproof layer) is usually non-woven fabric, which has undergone hydrophobic treatment to block liquid droplets and large particles. The intermediate layer (filter layer) is a key component, made of meltblown fabric (electrostatic polarization process), which can adsorb small particles, bacteria, and viruses. The inner layer (moisture absorbing layer) is made of soft non-woven fabric, which is skin friendly and moisture absorbing, improving the comfort of wearing.