Premium humidifier wick filter compatible with Vornado humidifier It's compatible with Vornado Evap3, Evap40, Evap1, Model 30, Model 50 evaporative humidifiers. Also, model number 221, 232, 421, 432, HU1-0021, HU1-0006-11, HU1-0007-11 Compared to Vornado part MD1-0002 Help trap mineral deposits from water Suggested replacing the filter every 3 months and 2 months if using the humidifier every day. Dimension: 7.25"H x 9.5"L x 1.5"W. 10 filters included. Premium humidifier wick filter compatible with Vornado humidifier. It's compatible with Vornado Evap3, Evap40, Evap1, Model 30, Model 50 evaporative humidifiers. Also, model number 221, 232, 421, 432, HU1-0021, HU1-0006-11, HU1-0007-11. Compared to Vornado part MD1-0002. Dimension: 7.25"H x 9.5"L x 1.5"W. 10 filter included.