HUMIDIFIER FILTER: This PDC51CV1 humidifier demineralization cartridge work with these Vick Ultrasonic humidifiers: V4600, V5100 and VUL575, and Sunbeam696. Not Work with VUL525, VUL545, VUL530, VUL565, V5200 Series! Please notice: This PDC51CV1 humidifier demineralization cartridge be used in place of kaz dc-51 filter! USE WITH TAP WATER A Demineralization Cartridge for humidifiers may be especially helpful in areas where there is hard water. Use it to help capture the minerals in your water before they are released into the air. REDUCE THE WHITE-DUST - This PDC51V1 Demineralization Cartridge for humidifiers aims to reduce mineral (calcium & lime) buildup and white dust caused by hard water in ultrasonic humidifiers. Reducing calcium and lime buildup may help extend the life of the humidifier and facilitate routine maintenance. LONGER LIFE - Use a replacement cartridge as necessary; every 2-4 weeks or 15-30 fillings under normal use or when the humidifier has not been run for an extended period of time.