1.[Perfect Compatibility] Our filters are perfectly compatible with HSP001 Smart True HEPA Air Purifier and have been tested to fit tightly with HSP001 Air Purifier. 2.[4-Stage Filter Filtration] There are 2 types of filters in the package, 2 replacement filters in total: 1 filter A and 1 filter B. (Filter A 2-in-1) One side is: Gray Cold Catalytic Filter, the other side is: Activated Carbon Filter. (Filter B 2-in-1) One side is: Blue Pre-Filter, the other side is: H13 Grade True HEPA Filter. They can effectively reduce pet dander, cooking odors, pet odors and smoke. A total of 4 stages of filtration, which can significantly improve the air quality in your room 3.[H13 Medical Grade True HEPA] In order to improve the filtration efficiency, we adopt H13 True HEPA as the replacement filter set, which can help filter 99.97% of airborne particles as small as 0.3 microns 4.[Save Money] Contains 4 sets of low-cost replacement filters. Our HSP001 filter set is designed to reduce your budget with . So if you are considering which seller to buy your HSP001 air purifier from, please choose us without hesitation. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.