This is warning to all of my fellow HVAC Contractors! The Rotobrush duct cleaning machine is a RIP-OFF! The cost of this product is outrageous compared to the return on investment. The cost range from $XXXX-$XXXXX. The machine is a plastic box with a motor & circuit board in it. It breaks pretty easily and the suction that it produces, SUCKS! I was a sucker that purchased it think that it would add income to my business or maybe help close on some installs but neither has occurred. Buyer beware!