Features: 100% brand new and high qualityEasy to Use: Simply drop it in tank, for fresh, pure mist. Replace cartridge every 30 days.This humidifier tank cleaning ball contains no harsh chemicals.Eliminates Mineral Build-up: the Cleaning cartridge helps to prevent and reduce the white-dust caused by minerals in hard water. This hard-water"dust"can contain calcium, lime or .Humidifier Cleaner: Works in virtually all humidifiers, including the following types of residential humidifiers and vaporizers: Ultrasonic, Cool Mist (impeller), Warm Mist, Evaporative and Steam Vaporizer. Also works in fish tanks.Purifies Water: Reduces up to 99% of odor causing harmful substances growth. Keeps your humidifiers mist clean and less tank cleaning times.Colour:blueMaterial:plasticPackage Contents:5 x Humidifier CleanerOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.