Duracraft AC-814 Humidifier Filter, Compatible Replacement, 2-Pack Fits Duracraft Natural Cool Moisture Models DH-836, DH-837, DH-837B, and DH-950 Measures approximately 5 -1/2" x 6" x 1-1/2" MicroFree antimicrobial technology prevents surface growth of mold, fungus, algae and bacteria. Lasts the life of the filter. Pack of 2 Duracraft humidifier wick replacement filters Recommended replacement: at least once each season; more often in hard water areas.