Premium 3-in-1 True HEPA with activated carbon filter compatible with Compact Air Purifier. | Preliminary Filter traps visible debris such as hair and dust. | High quality HEPA filter capture 99.97% of airborne particles down to 0.3 microns. | Pre-filter and carbon filter remove any unfavorable household odor and trap the dust.|Dimension 7.5 x 2.4 x 7.5 inches. Suggest replacing the filter every month the most to maximize the performance.