perfect fit: With our true HEPA filters, ensure a perfect fit and compatibility with HY4866 and YIOU M1 air purifiers. However, it is recommended to ensure the model before purchasing. Innovative True HEPA Filtration: Adopts a unique honeycomb activated carbon structure that enhances purification effects and extends the lifespan. This improved filtration ensures optimal performance and efficiency of your air purifiers over extended periods. Economical and: Pack includes 2 filters compatible with HY4866 air purifiers featuring a lifespan of 8800 hours. To maintain ultimate purification performance, it is recommended to replace the filters every six months; although this may vary depending on usage and environmental conditions. Quality Promise: While extending the durability of your air purifiers, we also prioritize the quality of our HEPA filters. Ensuring that are of high quality, we guarantee that are HEPA tested to meet standards for your family's safety. First and foremost: Ensure