Usage Tips:[Perfect Compatibility]- 2 pack for blue pure 511 replacement filters ONLY compatible for Blue Pure 511 Air Purifier. Please confirm your air purifier models and the filter dimensions before purchasing. Filter Height: 8.27in (21cm), Width: 7.87in (20cm). Note: Do not fit for 311 Auto,411,411i Max, 211i Max, 311i Max, 311i+Max. ONLY compatible for Blue Pure 511 311i+Max. ONLY compatible for Blue Pure 511 This replacement filter for 511 air purifier adopt advanced lower energy consumption and lower density structure, ensuring higher efficiency and less pressure to maximum filtration and longer lifespan [High Efficiency Filtration]- for Blue Pure 511 filter replacement is designed with a double layers high efficiency filtration system. The H13 True HEPA filter effectively attaches 99.97% of airborne particles down to 0.3 microns such as pollen, dust, pet dander, and other tiny particles. Additionally, the Activated Carbon Filter swiftly and efficiently tackles household odors from pets, cooking, smoke, wildfires, and VOCs, ensuring a fresher and cleaner indoor environment [Easy to Replace & Install] - These 2 pack for Blue Pure 511 air purifier filters features a design for space-saving convenience and excellent cost performance. It is recommended to replace the 511 air filter EVERY 6 MONTHS, or depending on air quality and usage frequency. The Blue Pure 511 filter's small tags facilitate easy removal and replacement without the need for tools Color: White Material: Filter Paper Package Contents: 2 pack 511 Replacement Filter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.