K7M Re Mineralizing Water Filter Cartridge Final Stage Final stage filtration and water conditioning for Aquaphor RO101 Water Filtration System Use Enriches and conditions purified water so it is tastes better; concentration of mineral elements 0.2 to 0.5 ppm Push and Turn Technology allows easily replace cartridges with no tools NSF and LGA certified BPA free ISO 9001 standard Recommended to be replaced once a year depending on incoming water quality and usage