HEPA Easy Twist Cartridge 16 inch, Single
Fit Model 3000, 4000 ,AW350 & AW675
Molded cartridges fits old models, In Molded cartridge HEPA filter is open from both sides and sits in unit freely. While Easy twist HEPA cartridge is closed from one side and you have to twist it in unit to lock the filter. Molded cartridges will soon be discontinued.