BestAir A12W-PDQ-6 Humidifier Replacement Paper Waterpad Filter, for Aprilaire, Chippewa, Humid-Aire Neptune & Walton Models, 15" x 11.6" x 2", Single Pack

Waterpad that fits: Aprilaire 112, 136, 224, 440, 445, 445A, 448 (12); Chippewa 224, 225, 226; Humid-Aire Neptune; Walton 600, 620, 660. Uses up to 50% less water. Anti-Microbial helps protect filter from the growth and Migration of Mold, Fungus, Algae & Bacteria. For Best Performance, change at least twice per heating season, maybe more depending on water conditions & frequency of use. Made in the USA