HUMIDIFIER MODELS - Replacement filter for Humidifier models: 3020, V3100, V3500, V3500N, V3600, V3800, V3850 , V3900 etc. 4 PIECES OF - It is a great, affordable option for your home humidification. Increases humidity during dry seasons to create a comfortable home environment. Pack of 4 humidifier replacement filter, regular replaced to prevent excessive drying into your house. PerfectREPLACEMENT - Filter captures minerals and pollutants from water & helps prevent white dust. It has improved filter design that maximizes moisture output. The filter material is reinforced for maximum efficiency and filter life. FILTER TIPS - The discoloration of humidifier filter is natural and will vary depending on water. To maintain maximum filtering performance, filter should be replaced about every 1-2 months (Depending on use and local water quality), or when performance starts to deteriorate. If you notice a amount of impurities in the filter, or notice a persistent odor caused by poor water quality, replace the filter more frequently. Colour:White Material:wood pulp paper Size:20.5 x 13 x 2.2cm Package Contents: 4 x humidifier filter 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 measurement allowed error is +/- 1-3cm.