The 2-Pack Air Purifier Replacement Filter for KNKA APH4000 is a set of high-quality filters designed specifically for the KNKA APH4000 Air Purifier. These filters are grade new and include two units of HEPA and activated carbon filtration technology, ensuring clean and fresh air for your home. The filter frame is made of aluminum, and the filter media is cotton, providing efficient filtration and maintaining the performance of your air purifier. Ideal for improving indoor air quality, this replacement filter set is a reliable and essential component for keeping your living space healthy and clean.