USB Air Purifier GMAP-U03 Combines the function of Tio2 photocatalyst and actived carbon filter to filtrate the dust and paticulate in the air High concentration negative ion which contribute to decompose or exterminate various contamination including dust ,particulate,allergen,odor,smoke,bacteria,molds ect. Optional fragrance slice for aromatherapy. Room area served:15O. unit dimension:99*85*90(mm).