.
Vintagevaclover I think it was one of the last Concept I models produced.
I love Concepts and buy them pretty much whenever they turn up.
I started vac collecting a few years ago and i have noticed how great vacs like these are fewer and futher between each year.
Concerning the Concept I that started the thread, it may just be a wheel making the noise. It's a very old thread so no doubt he worked it out.