... *35*37.5cm NW/GW: 7.5/9KGS 1.Clean air with ionization .Sreams of harmless negative ions pull in polluted ... air, trap contaminants and release clean, healthy air. 2.Whisper silent operation .So quiet ,you ... ,with the addition of a bulit-in fan , which increases air circulation therefore making ionic whisper more ffective . 4.Never needs replacement ...