At 1-inch thick, these Vornado MD1-0034 Humidifier Replacement Wicks (2-Pack) are designed to fit Vornado EV100, EV200, EVDC300, EVDC500, Evap2, and Evap40 evaporative humidifiers. An antimicrobial treatment helps protect the wick filter from bacteria growth. No cleaning is required and the wicks are disposable. The superior performance promised of Vornado's evaporative humidifiers is realized only when genuine Vornado wicks are used and replaced at the recommended intervals. While other brands may fit our units, these wicks do not carry the same quality and life as our own and can diminish the humidifier's performance. Vornado wicks are developed from the highest quality materials that work to absorb the maximum amount of water while filtering the circulating air.