16 Inch HEPA Cartridge for Amaircare 3000 Made After 2015 and Other Units 16 Inch Easy Twist HEPA Filter Cartridge 90-A-16ME-ET for Amaircare 3000, 3050, 4000, 4050 and 4000V, 5000V HEPA Air Purifiers. No air purifier is included: this is the 16 Inch HEPA cartridge. Also fits Air Whisper 350 and 675 units. Note: Must use only in units made after 2015. Use two units in Amaircare 7500 units . Easy twist has a solid lid (no hole in the middle) with a sign that says twist and turn. 100 square feet of HEPA filtration material. Captures smallest particulates. Replace in 2-5 years, more often if in dusty environment. If not significant airflow reductions occur. Always replace a HEPA air filter if an air purifier is turned off for more than 3 to 5 days. HEPA is a medium in which bacteria, viruses, etc. can grow if moisture collects in the filter media. Constant air flow keeps the HEPA filter media dry and free of such contaminants. Note: Filters not returnable unless deemed defective by manufacturer. Please be sure to order the correct size and type for your Amaircare unit.