I bought this to use on an 80w laser tube conversion. The unit is very well made and the earth pin has continuity with the body of the unit which is not always the case with imported items. I filled mine with distilled water to prevent any limescale build up, you can see the level on the sight glass on the front. It has an audible flow alarm as well as cut out connections via a supplied plug on the rear. I connected these in to the flow cut off in my laser controller and it works faultlessly. The wiring diagram could be a little clearer but if you meter the connections out there are options for normally open and normally closed. All in I'm very happy with the quality, price and delivery on this unit. My unit was despatched from Germany but I was able to track it all the way.