I ordered two and installed an air valve to eliminate the time it takes to pump. You can just plug it directly to an air compressor and pump it to 50 PSI and foam the car or the wheels. Once the foam starts to loose pressure, no need to manually pump, just slap the air pressure back on and continue foaming. This really works amazing well with brake dust on wheels. I specifically bought this to knock out the wheel cleaning process every week as quickly as possible. You can fill to 50 PSI and knock out all 4 wheels. The key is not letting it build up and of course using a great non-acidic wheel cleaner.

I'm selling it for $130.

Here's a video demonstrating how it works: