FilterBuy Replacement Filters Compatible with Holmes HWF55, Vornado 221, 232, 421, 432, HU1-0021. Pack of 6. Pack of 6: FilterBuy replacement filters compatible with Holmes HWF55 or Vornado 221, 232, 421, 432 & HU1-0021. Manufactured by FilterBuy be compatible with the following model #'s: Holmes HM1000, HM1025, HM1050, HM1550, HM1555, HM2000, HM250, HM405, HM406, HM725, HM726, HM730; Vornado 221, 232, 3120-900, 321. Also Fits Super Models #'s 43-5014-6, 43-5024-2, RW-3, & RW3 and Touch Point KS55EE-06A. Premium humidifier wick filter designed by FilterBuy to reduce pollutants. Replace at least once per season. Humidifier FilterBuy: Breathe Better!