Advanced Filtration Tecnology: The filter element of this mask has 5 layers of protection, bringing you a safe breathing experience.Warm Tips: Masks Replacement Filters, disposable supplies cannot be washed. Recommend replacement of 1~2 times a week.Safe Breathing :With 5 layers of protection,it can bring you a safe breathing experience.Unique Ventilation Design:Excellent permeability easily be doubled up for extra protection.Suitable for prevent fog, haze, vehicle exhaust, passive smoking,etc. Reusable Material: Made of active carbon filter,it cannot be cleaned.So,it is recommended to replace it once a week. Mask for air pollution.(1 Pack = 4 filters)