Aftermarket replacement humidifier filter designed to restore efficient operation for compatible MoistAir EF1 and EF21 units. This two pack provides reliable filtration, straightforward installation, and long service life. Key benefits Restores humidifier efficiency by capturing mineral deposits and debris that reduce vapor output and clog components. Durable construction resists tearing and fading for consistent performance over time. Simple dropin installation for quick filter changes with no tools required. Two filters per package provide an immediate replacement and a spare for routine maintenance. Product features Size: 8 in x 31 in x 1 in. Compatibility: Fits MoistAir EF1 and EF21 models. Quantity: 2 filters included per package. Material: Robust, serviceable filter media designed for long life and reliable operation. Practical use scenarios Seasonal startup: old filters at the beginning of the humidification season to ensure the unit runs efficiently from day one. Routine maintenance: Keep a spare filter on hand and swap filters at recommended intervals to prevent buildup and maintain airflow. Property maintenance: Use when servicing multiple units in a home, office, or rental property to keep humidifiers functioning properly. Additional information This is an aftermarket replacement part sold as a compatible alternative for the listed models. Includes a 30 day moneyback period and an 18 month limited . If you are unsure about fit, verify your unit model and serial number before .