I believe this version is Krupp built, PaK 43, on the 4 legged platform, similar to the Flak mounts. The information I have states that production of guns out stripped production of mounts, so as a stop gap measure, some guns were mounted on a conventional 2 wheeled, split trail mount ( PaK 43/41 ). Notice the absence of a recuperator over the barrel, and the vertical sliding breech block as opposed to the horizontal breech.