Korean KF94 mask is not a disposable mask, the use of time limit up to 48 hours, and KF94 mask main dustproof function. KF94 mask letter KF represents the Korean standard, the letter 94 represents the level of protection, for 0.4μm diameter particles filtration rate is greater than 94%, suitable for heavier air pollution, virus ridden environment. kf94 is not for medical standards, there are four layers. 1, the surface layer is a non-woven fabric that blocks outside dust; 2, the isolation layer is a non-woven fabric that enhances protection and reduces the risk of infection for users; 3, the filter layer, the electrostatic filter layer can effectively isolate fine dust and harmful allergens; 4, the skin-friendly layer, adsorbs moisture generated when breathing, keeping it dry and comfortable when worn.