Most keg couplers work the same, with many similar parts. The Guiness "U" coupler is no exception. It too has a check valve ball and a retainer for the ball. The Guiness ball and retainer are, however, different, and thus require different replacement parts that the reguilar. If you are in need of a new check valve retainer for your Guiness coupler, look no further than Great Fermentations!