Usage Tips:Product description: healthy air, advanced humidification filter, bacteria and scale can be adsorbed A air filter that can replace the filter of your Air humidifier. Go back to the fresh air and breathe again! FOR philips Air humidifier filters HU3915/HU3916/HU3918/HU2716/HU2718/FY3446 models Replacement accessories Maintenance:The filter should be replaced 6-10 months. But the replacing period also depends on how often you use your filter and around the environment. Material:filter paper colour:Blue Package Contents: 1 x filters Only the above package content, other products are not included. Note: Light shooting 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.Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.