CLEAN: These air filters achieve an efficiency rating of 99.97% against oily aerosol particles down to 0.3 microns to keep your air quality high SENSITIVE: The addition of the DOP filter adds a high efficiency, 3-stage air filtration ready for any sensitive job needing HEPA filtration QUALITY: B-Air HEPA air filters pass laboratory testing when installed as part of three-stage filtration process for the highest quality and clean air VERSATILE: Our air filters are 16 x 19 x 2 inches and are equipped for a wide range of enviornments that require first-pass efficiency air filtration COMPATIBLE: Our air filters fit well with the AS-550 from Blu Dri Air Scrubbers as well as other brands like Dri-Eaz, Phoenix, and Bear