Why choose our HEPA air purifiers? 1. We have our own factory and many sales channels. Walmart is one of our sales channels. Our factory sell nearly 1 million air purifiers a year and are a professional seller in this market worthy of your trust. 2. We have professional and complete technical and safety certifications as well as excellent and satisfactory after-sales service. We are not just make money we also hope to work with all humanity to maintain the earth s environment that we rely on for survival. 3. This air purifier can purify 2500 sq.ft in one hour. And it can effectively purify smoke dust pet hair odors in the air. 4. We provide a 3-year quality assurance for your air purifier. You can ask us any questions at any time and we will answer them within 24 hours including holidays.