I’m not too knowledgeable about plastic vacs or Dysons but this one is clearly interesting, especially the “dual cyclonic” part. What makes it dual as opposed to regular cyclonic like a Compact or Filter Queen? From the FQ style layout it surely looks like a machine that could pull some serious suction with a powerful motor. 

I’m confused on what it has to do with Dyson though: the machine is labeled both Johnson and Victor, while the seller thinks it’s a Hoover. Did Dyson design for Johnson/Victor or Hoover before starting his own company? Did Hoover actually manufacture it for Johnson/Victor?

That thing is complex! I'm assuming the idea is to first separate the lighter soil from heavy soil by forcing the heavy stuff to collect in the outer chamber and then the lighter stuff is sucked into the inner chamber where it drops out before the air is then sucked through the filter and into the fan. What does the filter look like?