The Jolie Replacement Filter fits inside the neck of your Jolie Filtered Showerhead and needs to be replaced every 90 days. Jolie made their 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. THE DETAILS The Jolie Filtered Showerhead sold separately Measures approx 2.4" W x 2.7" H Revolve Style No. JOLR-WU4 Manufacturer Style No. SHWR-FILTER-850036402138-BM Actual packaging and materials may vary. Please read labels, warnings, and directions before use.