pasutech Holmes HWF65 Humidifier Filter (Aftermarket) Fits Holmes humidifier models HM5100, HM1800, HM1840, HM1845, HM1850, HM1851, HM1855, HM1865, HM1888, HM1889, HM1895, HM1975, HM2059, HM2060W, HM2090, HM3000, HM3800, HM3850, HM7600, and HM4000. HM3000 and HM4000 require 2 filters. HM3800 and HM3850 require 3 filters. Holmes aftermarket humidifier wick replacement filters. Measures approximately 7 1/2" H x 5 1/4" ID x 7 1/4" OD x 1" Thick. With antimicrobial agent! This is an aftermarket filter.