✔ 5 Layer Protection --- This filter element has 5 layer protection, bring you comfortable breathing experience. ✔ High Quality --- Ultrafine filtration spray cloth, auxiliary filtration of 0.5 micron dust dust smaller harmful substances. ✔ Personal Protection --- Special 5 layer activated carbon filter, can effectively filter pm2.5 haze and fine particles such as dust, secondhand smoke prevention and automobile exhaust protection.