Made of natural fabric with a multi-layer mesh surface to enhance humidifier moisture output and improve limescale filtration. Upgraded material provides increased stability and filtering efficiency for extended use. Compatible with WF813, RCM-832, RCM-832N, Pro Care PCWF813, PCWF-813, PCCM-832N, PCCM-840, EQ-2119-UL, DH-830, DH-832, AC-813, ACR-832, D13-C, HC-832, and similar models. Easy installation: Remove the old filter cartridge and replace it with this one. Adjust properly for optimal performance. Replace every 1–3 months under normal use. Use only distilled or cold water in the tank; do not use hot water. Color: White Material: Wood pulp paper Package Contents: 5 x WF813 Humidifier Filters Note: Light reflection and display differences may cause slight variations in color between the image and actual item. Measurement error allowance is +/- 1-3 cm.