Carbon Activated Pre-Filter 2-pack for use with the GermGuardian FLT4825 HEPA Filter, AC4800 Series, Filter B 2-Pack of Carbon Activated Pre-Filters Made in the USA from BulkFilter Brand Material These PreFilters are designed to fit FLT4825 True HEPA Replacement Filter for AC4800 Series, Filter B Carbon Activated filters extend the life of the hepa filter and remove common household odors Each filter is 4.8"x15.75" and is desinged to be a direct replacement for existing Pre-Filter MADE IN THE USA