The Omnipure E5721 10 Mic CTO cartridge was made to fit Omnipure E-Series heads as well as existing Everpure® heads with a collar. This filter reduces chlorine, taste, and odor and has a capacity of 3500 gallons. The new E-Series was designed for those customers that are using existing permanent heads but would like an alternative to the replacement bodies offered. They offer equal or superior filtration capability at a considerably lower price than comparable OEM filters.Specifications: Everpure® S-101 Compatible Fits ROM II & III systems 10 micron Coconut Shell Carbon Block Taste, odor and chlorine reduction Class 1 filtration media Maximum one-year service life NOTE: *Everpure®" is the registered trademark of Everpure, Inc. of Northbrook, Illinois 60062 the manufacturer of Everpure® brand water treatment equipment. The replacement water filter listed above is not manufactured or endorsed by Everpure. Rather, this filter is manufactured by Omnipure Corporation. While this filter is compatible for use in Everpure® brand water treatment equipment, we make no representation as to whether using this filter is consistent with the warranty applicable to Everpure® equipment. Compatible Filter Heads Non-Compatible Filter Heads QL2 QL3 QL7I: Single Head QL1 QL3B QC7I: Multi-Cartridge Head Manifold