Made of natural fabric with a multi-layer mesh surface to maximize humidifier moisture output and better filter limescale. The upgraded material provides improved stability and filtration performance for extended use. Compatible with 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 similar models. Easy installation: Remove the old filter and replace it with this new 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 between the item color shown and actual color. Measurement error allowed is +/- 1-3 cm.