High Compatibility: The 100% PP Polypropylene is compatible with a wide range of water types. Three Layered Cartridge Tech: To give you fresh clean water every time. Melt Blown Manufacturing: This manufacturing technique enhances the natural taste of water. Individually Wrapped Cartridges: All cartridges come individually wrapped to improve your shelf life. BPA free components: Our filter systems doesn't contain Bisphenol A or other toxic plastic materials. Max Water Melt Blown Whole House Water Filter Replacement Cartridges is manufactured from 100% Polypropylene construction offering excellent filtration and good thermal stability. Designed as three-layers structure cartridge for high contaminant holding capacity and dual gradient density filtration.