These replacement filter are and high-efficiency filter materials and practical Filter reduce the penetration of, pollens and other allergen into the air you breathes It is recommended that you replace part every 3 to 6 months Regular replacement of part will help your machine run at efficiency Suitable models: suitable for D600 D601 Package includes: 5 Pcs filter Easily Replace Press the button to open the bottom cover of the cup, rotate the filter and take out the filter