Building pit 105c, Bauwerk 9, Stp Prostki
There were three 105c casemates projected around the central 112b. Only two were finished. This must be the building pit for the thirth one.
View from the other side. The dimensions match a 105c.
The pile of earth which came out of the pit still lies next to it. It was used for some trenches and Kochbunker.