This is a model of German V-2 rocket support vehicle (WWII). A-Stoff was designation for liquid oxygen bowser, usually towed by Hanomag SS-100 heavy tractor. Liquid oxygen was used as a component for V-2 fuel. A rocket was filled up with liquid oxygen not early than one hour before start, otherwise some parts of the rocket could be frozen and damaged. A-Stoff was part of V-2 mobile battery, which consist of many other vehicles, that you can find among my other products. This is good choice if you are interesting in V-2 history. For more information about 20-ton heavy tractor Hanomag SS-100 see it individually in Suggested Product.