There were 5 such bunkers on the training ground and all of them were in the highest resistance class, i.e. III. Three of them, Wrangel, Gneisenau, and Scharnhost, are artillery observation shelters with a 360-degree field of view and four observation slots. The other two were to Lutzow and Yorck, which had only 2 slots, i.e. a 180-degree field of view.
Bunker named after August Neidhardt von Gneisenau
pl.wikipedia.org/wiki/August_Neidhardt_von_Gneisenau