Upgrade RO Reverse Osmosis with 58 Minerals inline filter / Re-Mineralization Contents 57 mineral elements Maifan Stone has function of two-way regulation of trace elements (microelements) and constant in water to reach the best balance of human body needed Maifan Stone balls can improve biological activity of the water with dissolved oxygen concentration. It enables the water degraded. Its replacement can remove harmful heavy metals, so the mineralized water produced by Maifan Stone is called "cell detergent" Maifan Stone filter has a adsorption. Maifan Stone has a adsorption ability to heavy metal ions and toxin in the water. This filter does NOT change water pH