1.[COMPATIBLE AIR PURIFIER MODELS]: FLT4825 HEPA Filter B Widely compatible air purifier models AC4825, AC4825E,AC4825W,AC4300,AC4900,AC4870,AC4820,AC4300BPTCA,AC4300WPT,AC4900CA,AC4850PT,CDAP4500BCA,CDAP4500WCA,P-Guardian Model AP2200CA and Black plus Decker BXAP150.NOTE:This is not a OEM product but compatible with replacement filter.Any use of the brand name or model designation for this product is made solely for purposes of demonstrating compatibility. 2.[H13 TRUE HEPA FILTER B]:The High-efficiency FLT4825 HEPA B air filters attaching 99.97% of dust,pollen,pet dander and wildfire smoke particles down to 0.1 microns from the air.Provide you the fresh and clean air all the time. 3.[ACTIVATED CARBON PRE-FILTER]:The activated carbon pre-filter of FLT4825 filter b collects dust,pet hair,and other large particles, while extending the life of the HEPA filter.Treated carbon take in volatile organic compounds from the air and reduces odors from smoking, cooking and pets. 4.[VALUE PACKAGS]:Package includes 4 x H13 True HEPA Filter B and 8 x Activated Carbon Filters.HEPA Filter Dimensions: H: 15-7/10" x L: 4-1/2" x W: 1-3/10",Carbon Filter Dimensions: H: 15-7/10" x L: 4-1/2" x W: 1/5".For the performance,it is recommended to replace the HEPA filter every 6-8 months,replace the activated carbon pre-filter every 2-3 months for the performance (depending on your usage and environment),and obtain higher filtration performance for long-term use.