The Omnipure E5685 is an All Phosphate Scale Inhibitor water filter. This filter also features a universal cap that fits all permanent existing heads which makes this filter easy to install and remove. This filter also aids in the removal of scale and prevent scale build-up in your pipes and on your fixtures. Additional Details ------------------------------ Product description: The Omnipure E5685 is an All Phosphate Scale Inhibitor water filter. This filter also features a universal cap that fits all permanent existing heads which makes this filter easy to install and remove. This filter also aids in the removal of scale and prevent scale build-up in your pipes and on your fixtures.