Well, I found the website:
Liberator Fuel Saver - Save gas and fuel for diesel, cars, semi-trucks, suvs, trucks and more! Gain more miles per gallon (MPG)
I have a hard time believing that somebody with a Hummer going from 10.5 to 14 mpg with this gizmo?? A 33% fuel economy increase? Where's the flux capacitor?
I'm able to match the 3.5mpg increase with my truck, but only if it looks like a MadMax reject with all the black plastic aero panels I strapped to it.