Made of natural fabric with a multi-layer mesh surface to maximize humidifier moisture output and effectively filter limescale. The upgraded material enhances filter stability and performance, allowing for extended use. Compatible with models WF813, RCM-832, RCM-832N, PCWF813, PCWF-813, PCCM-832N, PCCM-840, EQ-2119-UL, -830, -832, AC-813, ACR-832, D13-C, -832, and others. Easy installation: remove the old filter and replace it with this new one, ensuring proper adjustment. Replace every 1 to 3 months with normal use. Use only distilled or cold water in the tank; do not use hot water. Color: White. Material: Wood pulp paper. Package includes: 5 x WF813 Humidifier Filters. Product contents limited to items listed; other accessories not included. Note: Lighting and display differences may cause slight variations in color. Measurement may vary by +/- 1-3 cm.