Vickers Tank Periscope MK.IV
Vickers Tank Periscope MK.IV (invented by engineer Rudolf Gundlach) was first patented in 1936 as Gundlach Peryskop obrotowy. It was the first utility to allow the tank commander to have a 360 degrees radius of sight from his turret. Also, the main advantage of this periscope was that the tank commander did no longer have to turn his head in order to look backwards.
The design was first used in Polish 7-TP light tank. Shortly before the war it was given to the British and used in most tanks of WWII, including British Crusader, Churchill, Valentine, Cromwell and american Sherman. The design was later copied and used extensively also in the armies of USSR and Germany (among others in the Soviet T-34).
