The Puredry PD Mist Design HEPA filter is a 2-in-1 replacement filter for the Puredry PD Mist Design humidifier. It combines a HEPA filter and an activated carbon filter: the white side is the HEPA filter and the black side is the activated carbon filter. The HEPA filter captures 99.97% of particles as small as 0.1 microns, such as fine PM1 dust, pollen,...