The Omnipure K-Series K2520-JJ inline filter is a carbon block inline filter. This filter has 1/4 QC fittings. This filter can be used as a post R. O. filter. The K2520-BB can be used in refrigerators, ice makers, and any kind of under counter reverse osmosis or water filtration unit. This filter aids in the removal of sediment, taste, odor and chlorine taste and odor.