It looks like it would be a very nice looking diffuser. But, why would you care what it looks like if it is under the tank in the cabinet? So, that's one strike against it. Then, it is awfully small for an inline external diffuser, with a minimum of dwell time for the CO2 bubbles in the slower water flow. (Two strikes) And, if it is connected as they show, it doesn't even have the advantage of counterflow to increase the dissolving of the CO2. (Three strikes!)