Air Innovations, 2 Pack, Silver, Universal Humidifier Demineralization Ceramic Filters, Uses Nano Technology To Stop, Trap & Destroy Impurities & Contaminants, When Clean Water Flows To Your Humidifier's Ultrasonic Atomizer Turns Creates Clean, Pure, Healthy Moisture For Your Family To Breathe, Powerful Hard Water Filters Help Prevent White Dust From Forming In Your Humidifier By Removing Calcification & Other Impurities In The Water, Filter Will Last Up To 45 Days Depending Upon Usage & Water Quality, Works With Most Air Innovations Humidifier Models Including MH-408, MH-505, MH-509, MH-512, MH-513, MH-519, MH-519a, MH-602, MH-603, MH-701, MH-701B, MH-701C, MH-702A, MH-801, MH-801B, MH-903XL, MH-903A, MH-904, Not Compatible With Any MH-901 Humidifiers.