Don Clark didn't 'invent' anything. Eureka was using this set up in the late 1960's - early 1970's as a power nozzle for their commercial canisters. Don Clark saw one, and asked Air-Way to obtain them and sell them to him exclusively with the 88 Mark II models. Air-Way had already done this with the Hamilton Beach upright, but it didn't pick up very well. The Eureka set up was much better. Once Eureka started making actual power nozzles in 1973, Air-Way built their own too, the RugMasteR. The Eureka upright vac as power nozzle could still be ordered by big distributors, like Don Clark, or the Air-Way built RugMasteR could be ordered instead. Once the cleaner went 'black and white' instead of turquoise or yellow, the Eureka built nozzle went away. There were two colors of the Eureka upright-as-power-nozzle. Yellow or Turquoise.