Interesting
That they call this an air flow concentrator. I always felt it was more of a device to grip threads and hairs and the nap and fluff it up and so the debris would be flung up better so it could be sucked up.
What I can say is that I notice a mild but definite difference in how the nap is lifted and how it picks up the debris off the carpet better when it is on then off. I usually switch mine to off as soon as I stop cleaning the carpet to keep the bar from getting damaged Should the tool be accidentally dragged on concrete or hardwoods which could be damaged by the gleaner itself as it hides away when it is off.
I’m sort of annoyed Aerus has discontinued the device even in its later form from the 70s. Now they are all just smooth metal bars but the marking on the tool is still there oddly.
Jon