The Omnipure (Q5654-C100E) is a cation exchange softening cartridge which reduces hardness and scale deposits. This filter features the optional Twist Tap in-head valve system, which automatically turns the supply water off when the body is disconnected from the head. This filter can be used in ice makers, refrigerators, beverage equipment, drinking fountains, under the sink systems, and reverse osmosis systems. This filter aids in the removal of Hardness and Scale Deposits. This filter also uses C100E FDA grade softener resin.