This is the replacement filter for the Breathe In Air Pro 1 air purifier. It is a 4-layer composite filter containing all four filtration stages in a single unit, designed for straightforward one-piece replacement with no tools required. The first layer is a primary pre-filter that traps floating pet hair, dust and large airborne particles. The second layer is a Medical Grade HEPA13 filter that captures 99.97% of airborne particles down to 0.3 microns including PM2.5, pollen, pet dander and airborne bacteria. The third layer is a biological enzyme filter that fully decomposes ammonia and organic pet odours at a molecular level, breaking them down into harmless molecules rather than simply masking them. The fourth layer is a plasma and negative ion module with reactive oxygen pet odour decomposition that eliminates bacteria, viruses and stubborn organic smells. The Air Pro 1 has a built in filter replacement indicator on the display that alerts you when it is time to replace. Replacement frequency varies based on usage and indoor air quality conditions. Using a genuine Breathe In replacement filter ensures your Air Pro 1 continues to perform to its tested and certified specifications. CE, ROHS, FCC, ETL and ISO9001 certified. Compatible with Breathe In Air Pro 1 only.