If you are mobile or a home enthusiast look at the Tornado Black and not the classic or the copys of the tool. It's developed to be used with a lower air compressor and still effective. It has sealed ball bearings inside the rotation set. I don't know how it's translate in the US system but 270l/m you need from the air compressor and a 13 gallon tank. Here are some links on the Tornado Black and the vacuum tool.

Z-020 Tornador Black Car Cleaning Gun, Z-020 Tornador Black

ZV-200 Tornador Velocity-Vac

Tornador Complete Cleaning Kit

/Tony