The filtering half mask is a complete respiratory protective device designed to be used for protection of the wearer against exposure to harmful aerosols of solid and liquid particles (dust, smoke, mist, fumes). The half mask is intended to be used for a maximum of a single shift (NR - Not Reusable). The half mask consist of filter material, head straps, nose clip, internal nose sealing and exhalation valve. The inhalate passes through the filter material and the exhalate passes through the filter material and the exhalation valve. The filtering half mask class FFP3 offers protection when the concentration of dispersed phase of aerosol does not exceed 50 times the threshold limit value (TLV).