The observation turret type "Panzerbeobachtungsstand 05" is quite common in the German Festen. However the light version is much more rare. Two of them were installed in Feste Kaiser Wilhelm II. The turret was between 10 and 17,5 thick. It weighted 7.500 kg including the 1.500 kg heavy equipment. The later consisted of a pair of binoculars and an optical range finder. For more information www.mutzig.net.