4-Pack Ultrasonic Demineralization Humidifier Replacement Cartridges | Removes Water Odor, Purifies Water, Filters Mineral Deposits | Prevents Hard Water Build-Up, Eliminates White Dust | HoMedics PREVENTS HARD WATER MINERAL BUILD-UP: If you have hard water, this Demineralization Replacement Cartridge is a must-have! The ultrasonic filter helps to prevent and reduce the white-dust caused by minerals and chemical in hard water. This hard-water dust can contain calcium, lime or magnesium ECONOMIC WATER CLEANSER: This includes 4 Demineralization Cartridges! The filters work with all HoMedics 1-gallon or larger ultrasonic humidifiers. Simply drop 1 filter into your humidifier tank to begin enjoying clean, pure mist. Each cartridge gets 30-40 full tank uses, depending on your water hardness EXTENDS THE LIFE OF YOUR HUMIDIFIER: If you have hard-water, that means you are getting build-up in your humidifier tank! The minerals can build up in your tank and its motor which can keep it from working properly. HoMedics Demineralization Filters can help extend the life of your humidifier motor and tank by purifying the water inside and keeping it clean SIMPLE INSTALLATION: These Ultrasonic Demineralization Filters, are easy to use. Simply drop 1 cartridge into your HoMedics humidifier tank and it will start to work WHATS INCLUDED: Includes 4 blue ultrasonic humidifier demineralization cartridges. Dimensions: 4.25"L x 1.00"W x 4.25"H