I discovered that the Hansgrohe installation unit (what I'd call 1/2 of a master cylinder) had water corrosion so our master bedroom shower was faulted and not working. I wasn't sure if it was the motor or the unit, but since the motor was $800 to replace, I started with the mechanical unit. Chicago Faucet was the only company in North America that I found that carries these unique parts, and better yet, they called to confirm that I ordered the right part and to let me know the delayed timing due to getting the parts from the manufacturer in Europe. Once the part came in, I was able to change out to the new part (instructions were great) and we have a shower again. Best thing is, the motor was still good, so I'd made the right choice and saved $800 (at least for now). I couldn't be happier with the product, but what I appreciated more was the customer service and communication from the Chicago Faucet Shoppe...many thanks!!!