Compatible With for Humidifier Filters Replacement Filters - Compatible with HTF600 Filter & Filter T. designed and manufactured for humidifier models HEV615 & HEV620 Upgraded Blue Pre-Filter Layer - Our premium upgraded blue layer pre-filter helps reduce the quantity of large particles circulating in your air Tips For Daily Use - For best results, flip your compatible for humidifier T filter daily and only fill humidifier tank with distilled water (this applies to all of filters). Hard water degrades ALL compatible for humidifier filters and yellows them prematurely Value Pack - Premium replacement for HFT600 Filter T filters for your HEV615 & HEV620 humidifiers. Made from high-quality, material with an upgraded filter design to both filter large particles and maximize moisture output Installation Instructions - Soak your replacement wick for T Filter for humidifier HEV615 and HEV620 in cool water before replacing to uninterrupted moisture output. Place in filter housing with blue layer facing outwards (towards you)