1. Compatible: This product is designed for Philips 800 series air purifiers. Compatible models include AC0830, AC0820, AC0819, etc. It serves as a replacement for original filters FY0194 and FY0293, ensuring a proper fit and performance. 2. Efficient HEPA H13 Filter: The H13 grade HEPA filter captures up to 99% of 0.3 micron particles, such as pet hair, dust, pollen, and mold spores. It also effectively removes harmful substances like formaldehyde, secondhand smoke, and odors, making it an ideal choice for allergy sufferers and pet owners. 3. Nylon Pre-Filter: The ultrafine nylon pre-filter traps larger particles like dust, fibers, hair, and pet hair. This not only improves indoor air quality but also extends the lifespan of the main filter. 4. Cost-Effective: Each pack includes 2 HEPA filters. We recommend replacing them every 12 months, though the exact replacement interval can be adjusted based on usage environment and frequency. A single pack meets your needs for a full year.