try this,http://www.precisiontrucks.com/TOTERgallery.htm, these are the style, but most now are conventionals, I see A Freghtliner cabover made it to the bunch,I don't believe there is a set limit, I have seen single sleepers,double bunks, as long as it can pull, it will work, I now see regular 3 axle trucks with the toter box added on going down the road, if I can find out more, I will let you know, I get the desire to try this one more every day....hahahaha