Vornado genuine humidifier wick are specially designed for our humidifiers. The filter must have the correct height, width, thickness, and material for maximum performance. Competitors often advertise their filters will work with Vornado humidifiers but these filters don"t always fit properly, therefore, the humidifier will not work effectively. Vornado wicks are developed from the highest quality materials that work to absorb the maximum amount of water while filtering the circulating air. Competitor brands are made of different materials not designed for Vornado humidifiers. Comes with 2 genuine replacement filters per box. It fits all models of Vornado Evaporative Humidifiers, including model numbers 30, 40, Evap1, and Evap2 series.