II WW German Kriegsmarine part of U-boot periscope optics

II WW German Kriegsmarine part of U-boot periscope optics. This item is in my family from early 50' when my father bring it home from Shipyard in Gdansk, Poland (Danziger Schichau Werft). Condition as you can see on photos. No maker's marks, possibly Carl Zeiss Jena.

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