The Jolie Replacement Filter fits inside the neck of your Jolie Filtered Showerhead and needs to be replaced every 90 days. We made our filter best-in-class by focusing on the two most effective filter mediums for the shower: KDF-55 and Calcium Sulfite. This is the good stuff — built to remove more chlorine & heavy metals than any other filter on the market. By subscribing, your replacement filter will arrive on your doorstep every 90 days — no need to remember when to replace. This is brand new! Nothing wrong with it / never opened, just don't need it.