Let’s clear the air. Blueair genuine filter for Blue Pure 211i Max air purifier. Blueair genuine Blue Pure F2MAX Replacement filter for 211i Max is designed for optimal performance; Not compatible with 211+ and 211+Auto. Get more out of your filter. Our proprietary RealTrack algorithm calculates filter lifetime based on actual usage and pollution levels and tells you when to replace within 9 months. Subscribe to save on auto-delivered air purifier filter replacement. When similar CADR was measured, Blueair models with mechanical and electrostatic filtration achieved less noise with less energy than same models with only H13 HEPA mechanical filtration. Tested PM 2.5 (0.1 - 2.5 microns) up to 90min in a 30m3 room. Tested to remove min. 99.9% of S. aureus, K. pneumoniae, P. aeruginosa, MS2, E.Coli, H1N1, A.Niger. Based on a survey of over 50 awards, accolades, and recommendations issued by independent consumer associations, media publications, and industry competitions from January 1, 2022, through January 31st, 2023, for products sold in the US by top 10 air purifier brands according to NPD Group Retail Tracking Service, Small Appliances, U.S. sales dollars Jan – Dec 2022.