Portal boxes can work on both solid and independently suspended axles. They use gears to lower the wheel relative to the axleshaft and thus allow the driven axle to gain ground clearance. This custom solid axlehousing with portals, built by Jesse Haines Fabrication, uses the internal parts from Hummer H1 axles, which you may or may not know, are independently suspended. Vehicles with portal axles available in the U.S. include the Hummer H1 and Mercedes Unimog. There are a handful of portal axles in the aftermarket that can be swapped onto some solid axles for Jeep, Land Rover, and Mercedes.