Thanks for the information. It must be, then, that the Prolux (and Prolux Plus) cleaners were part of the indirect sales line as an Aerus representative in corporate said that the only commercial uprights they've carried (presumably in its direct sales line) have been those that have had 'Commercial' in the name. The first one--according to my records--was the Model U120A/Commercial which premiered around 1994. The first Prolux cleaner, the Model 1400, was introduced in 1987 and has since been retired.
It is difficult to understand why the nameplates of commercial cleaners would read 'For Household Use Only', or is that just a legal requirement in case someone decides to vacuum his/her driveway or lawn then tries to claim that the unit was defective?
I think it's also interesting to note that the terms 'heavy duty' and 'industrial' are so ambiguous in the industry. I have asked several--including Aerus associates--what they mean and have been given different answers; some have even said they weren't sure. While it makes sense that different companies go by various standards one would think that the industry would have parameters as to what the terms generally include.