I am selling this filter because I no longer need it after disposing of the main unit. [Model Number] HV-FH7 Humidifying Filter. Material: PET and rayon. [Maintenance Guidelines] Once every two weeks. Clean the filter if the air blowing out smells or if the humidification amount decreases. If you continue to use the filter without cleaning it, it may cause the inside of the main unit to overheat, reduce the humidification amount, produce an unusual odor, or cause other malfunctions. [Replacement Guidelines] Approximately 8 seasons. The lifespan of the humidifying filter varies depending on the water quality.