Calcium Inhibitor Filter, Protects Your Misting Systems By Preventing Potentially Clogging Solid Sediments From Passing Through The System, Filters Our Particles As Small As 5 Microns, Filter Coats Smaller Particulates With Polyphosphates That Enable Easier Passage Through Nozzles Without Forming Blockages, Annual Filter Replacement Is Recommended & Will Prolong The Life Of Mist Nozzles.