Product review (2 stars): it does a wonderful job. This eliminated the excessive foaming caused by ...
When it works, it does a wonderful job.  This eliminated the excessive foaming caused by warm beer lines and tap.  It worked fine for about 2 weeks, then started making noise when it started up.  It's progressively gotten worse, I don't think it'll last much longer, which is a shame considering the price and what appears to be very cheap materials.  Good concept, poor execution.