The OmnipureK-SeriesK2328-JJ filter is a post r.o. system carbon filter. It ...The Omnipure K-Series K2328-JJ filter is a post r.o. system carbon filter. It has 1/4 FQC quick connect fittings that make it really to install and replace. It can be used in refrigerators ice makers and any under counter reverse osmosis or water...more