This 2-pack of HEPA replacement filters is compatible with AC4825, AC4825E, and AC4300 air purifiers. The filters are made of environmentally friendly non-woven fabric and activated carbon, with a filtration technology that captures 99.97% of particles as small as 0.3 microns. Each filter has a life span of 6 months and measures 4.7 inches in height and 15.6 inches in length. The package includes two filters, making it a convenient and cost-effective option for maintaining the air quality in your home or office. Keep your air purifier running smoothly with these high-quality replacement filters. COMPATIBILITY]: ELOWOKE HEPA Filter B replacement Compatible with FLT4825 Guardian air purifier models: AC4900CA, AC4870, AC4850PT, AC4825, AC4825W, AC4825E, AC4820, CDAP4500WCA, CDAP4500BCA, AC4300BPTCA and compatible with Pure-Guardian AP2200CA and compatible with B|ack-Decker BXAP148 [OPTIMIZED PLEAT DESIGN]: Redu?cing the gap size of true HEPA Filter to 3.5mm, and increasing the spread area to 8 sq.ft can significantly enhance filtration efficiency without compromising wind resistance. This feature guarantees rapid and efficient clearance of room air while maintaining a quiet environment with low decibel levels [TRUE H13 FLT4825 HEPA FILTER B]: Uses MERV 17 high-efficiency filter material to capture 99.97% of partic|es as small as 0.3?m. It's an excellent choice for improving indoor air qual?ty and ensuring a fresher living space [6 EXTRA ACT?VATED CARBON PRE FILTERS]: They effectively rem0ve od0rs, smoke, and VOCs from the air. These pre-filters can be used alongside your primary filter to improve air qual?ty and extend its lifespan [USAGE TIPS]: Package includes 2x FLT-4825 HEPA Filter B replacement and 8x Act?vated Carbon Pre Filters. It's recommended to replace the HEPA filter every 6-8 months and the pre-filter every 2-3 months, or as needed based on your environment