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 6 filters included. 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. 6 filters included. 100% customer satisfaction guaranteed. Quality meets or exceeds leading national brand 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. 6 filters included.