The American Plumber 555022-51 is the correct replacement filter for the following systems:
The American Plumber WROM-25T RO Membrane is a replacement water filter for use with the American Plumber WRO-4500 4-State Reverse Osmosis Drinking Water System. This RO membrane operates alongside the pre-filter, post filter, and polishing filter to reduce the taste and odor of chlorine, dissolved minerals and salts, and general bad taste and odor. The reverse osmosis membrane specifically purifies saline water and utilizes crossflow filtration to keep the membrane surface clean and prolong its life.
American Plumber WROM-25T RO Membrane specifications: