how wide is a Pro 30 Bio-Wheel set up?

[dax29]

I'm trying to find out how wide a Pro 30 Bio-Wheel is so I can decide whether or not to get it. I have limited room on the back of my tank. I have called Drs. Foster and Smith and a rep said it was 8.5", which just may work. I called Marineland and a rep said it was 10". I'm tempted to believe the Drs. F&S person b/c I know the Pro 60 is a little over 19 inches and that includes the space between the 2 wheels for the output pipe that goes to the spraybars. I don't want to buy something that won't fit.