ADVANTAGES OF REUSABLE FILTER TRACKS - Reusable and easy to replace. They make filters for your machine more cost effective and can reduce plastic pollution to be environmentally friendly. THE FOAM POLL & ULTRAFIN - The foam version is for blocking particles. The ultra fine version is to block fine particles. Use them together to provide the cleanest air. FOR HEALTHIER LIFE - Our kit is designed to provide you and your loved ones with the cleanest air to maintain the health of your lungs and keep the potential diseases away from you.Reusable filter opening Replace once every 3-6 months, ultra-fine disposable filters Replace every two weeks. Specifications: Applicable models: For DS500 / 700, etc Color: blue+white Material: ABS+Cotton Size: 5.7 x 2.5cm Package Contents: 6 x Reusable Filter Place Replace 6 x Ultra Fine Disposable Filters Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The permissible measurement error is +/- 1-3 cm.