Holmes® HAPF60-U3 Carbon Replacement Filter, 4-PackThis carbon filter helps eliminate odors for maximum comfort and freshness. Uses charcoal treated with oxygen to open up millions of tiny microscopic pores between carbon atoms. Effective in removing odors and pollutants from air passing through the filter. With Holmes brand technology, you can live in harmony with nature for a serene home environment. For use with select Bionaire brand air purifiers Carbon replacement filter For models HAP 625, HAP