Purification cotton ADVANTAGES OF REUSABLE FILTER SLOTS - Reusable and easy to replace. They make filters for your machine more cost-effective and can reduce plastic pollution to be friendly to environment.FOAM POLLEN & ULTRA FINE - The foam version is to block large particulate matter. The ultra fine version is to block fine particles. Use them together to provide the cleanest air. FOR HEALTHIER LIFE - Our kit is designed so as to provide you and your loved with the cleanest air to maintain the health of your lungs and keep the potential diseases away from you.Reusable Filter Slot Replace Once every 3-6 months,Disposable Ultra-Fine Filters Replace every 2 weeks. ADVANTAGES OF REUSABLE FILTER SLOTS - Reusable and easy to replace. They make filters for your machine more cost-effective and can reduce plastic pollution to be friendly to environment. FOAM POLLEN & ULTRA FINE - The foam version is to block large particulate matter. The ultra fine version is to block fine particles. Use them together to provide the cleanest air. FOR HEALTHIER LIFE - Our kit is designed so as to provide you and your loved with the cleanest air to maintain the health of your lungs and keep the potential diseases away from you. Reusable Filter Slot Replace Once every 3-6 months,Disposable Ultra-Fine Filters Replace every 2 weeks. Specifications: Applicable models: For DS500 / 700, etc Colour: blue+white Material: ABS+cotton Size: 5.7 x 2.5cm Package Contents: 6 x Reusable Filter Slot Replace 6 x Disposable Ultra Fine Filters