Compare with the one: Replacement filter compatible with Levoit Core 400S and 400S-RF air purifiers. Designed to fit your air purifier precisely. Why choose us: Perfect size, high quality, low noise, same technology, and less cost. Our Core 400S filter replacements offer a worthwhile investment for clean air. How does the filter work: The replacement filter features an H13 True HEPA filter, activated carbon filter, and nylon pre-filter. It captures 99.97% of particles as small as 0.3 micrometers and helps eliminate odors, VOCs, and other household smells. How to work perfectly: Replace the filter every 12 months, depending on usage frequency and environmental conditions. Easy to install with no tools required. Color: White Material: Plastic Package contents: 1 x Filter element Note: Only the items listed are included. Lighting and display differences may cause slight color variations between the product image and the actual item. Measurement error is +/- 1-3 cm.