HQRP Humidifier Wick Filter improves the efficiency of your humidifier on the trap hunting mineral deposits from the water. This 3-layer humidifier filter facilitates the spread of dust and dirt build-up and prevents impurities by passing air through the filter, also removes odours. For optimal performance, the humidifier filter should be replaced at the beginning of each season and then every 4-6 weeks, depending on the purpose and hardness of the water.