1.Compatible Models: Our replacement filters are compatible with Core 300 and Core 300S air purifiers, part number Core 300-RF.Please note: This is not the original filter cartridge, but the quality and performance is the same as the original. Please check the model before purchasing 2.3-Stage Filtration: The Core 300s replacement filter consists of pre-filter, H13 HEPA filter and activated charcoal filter; The H13 True HEPA filter captures 99.97% of particles as small as 0.3 microns to help you sleep easier and breathe easier 3.Affordable and Practical: Our filter replacements come in a 2-pack, providing nearly a year's worth of use for your air purifier. For optimal performance, it's recommended to replace the filters every 5-6 months, or based on your usage frequency 4.Easy to Install: The Core 300S filter uses the same installation process as the factory replacement. The replacement process is simple, no tools required, and can be completed in seconds.Create a y, fresh environment while you use your air purifier