Vornado Humidifier Mineral Cartridge Quantity of (2) : New Vornado Replacement Humidifier Mineral Cartridges Filters Out Minerals That Help Form The Residue Build Up Completely Odorless & Extends The Life Of Your Humidifier Contains A Special Blend Of Water Softening Minerals That Reduce Lime & Calcium Build Up For Use With Vornado Ultra3 Ultrasonic Humidifier model HU1-0031-06