▶Compatible Air Filte for air purifier AS401WWA1, 1 Filter +1 Pre-filters. ▶Replacement H13 Grade True Filter, and High Efficiency Activated Carbon Filter ▶H13 Grade Filter 99.7% of airborne particles down to 0.3 microns in size,High-Efficiency Activated Carbon, filter All sorts of and smoke ▶Please replace regularly to keep your machine fresh, Replace every 6-12 months depending on the usage and environment ▶Easy to replace, can be installed without the use of any tools, if any problems with the process, please contact us Compatible Air Filte for air purifier AS401WWA1, 1 Filter+1 Pre-filters.