This is a super rare scope used on a German U-boat during WW1 used on the 8.8 deckcanon Long 30 calibers.
8.8cm Ubts K.L/30 means 8.8cm Uboats canon 30 calibers long.
Ehrhardt was the inventor of the braking system of the canon, patented by him for the Rheinmetall canons.
The 30 cal long 8.8cm Canon was replaced at the end of 1917 by its larger brother, the L/45
In the beginning of WW1 ( 1914-1916) The German u-boats used to go to surface and shoot at the enemy merchandise Ships with their 8.8cm Canons, and sink them without using their expensive torpedo's.
This is the first German U-Boot-Zielfernrohr by carl Zeiss ive ever seen anywhere in the world of a 8.8 cm K.L/30 of WW1.
Having contacted Dr.Hans Seeger ( the binoculars and leading Zeiss specialist of the world) about this scope he came up with following:
The letters UHZ could mean U-Boot-Hilfs-Zielfernrohr, this is an auxilliary aiming scope. 1 x means= No magnification , this is confirmed by your picture.
Hilfs-Zielfernrohr would say: Can be used as a replacement if the main scope fails.
All surviving U boat where delivered to England and France after the war, most of them where distroyed.
France took 12 of them back to service and used them a couple of years.
Enjoy this Kriegmarine Scope of WW1