Product review (2 stars): Quality Control on push connector o-rings are a Concern
Purchased new filter housing because the newer Whirlpool filter elements with the same part number would no longer fit.  That is a manufacturing process no-no.  However, the old filter housing water connections did not leak.  Installed the new filter housing to get a filter to fit.  The larger 5/16 gray push in fitting is fine.  However, the 1/4 inch fitting leaks big time.  Removed and reinstalled very carefully.  Again, the gray 5/16 connector is fine, but the red 1/4 connector still leaks.  Plumbing supply clerk suspects faulty o-ring in red connector in new housing.  Need Amazon to advise.