Installs behind fifth-wheel on standard 34? frames. Because the Flip-Over ball rotates in its socket, hitch ball and coupler life are greatly extended. They don’t “grind” against each other when you tow. The other advantage of a rotating ball is that it stays “free” in its socket so you can easily turn it over when you want a level floor in your truck. Requires 10? on top of the frame and 4? down each side. Mounts with three 3/4? bolts on each side.