Here it is. It is a quite ordinary pre-WWII German side mount marked Akah. Akah = Albrecht Kind, Hunstig is a wholesaler to the trade.
Until a few years ago they were the foremost producer of scope mounts too. The mount top is clamped and locked to the base by turning the levers.
Windage adjustment is by the two opposing screws in the front end of the top.