German U-boat binocular

The size of your binocular would mean they are (at object lens size, almost!, 3.25") 7x80, not 7x50 as stated by Mike…
Binocular for use in poor light conditions (night) are much better with large object lens (ie. 80mm, lets in more light than 50mm, but this means a much bigger, heavier and cumbersome binocular), the magnification being 7x…
Binoculars with more than 12x magnification really need object lenses larger than 50mm…otherwise inefficient…normal naval binocular is 7x…
Day & Night and with the filters (Yellow) are especially (but not only) for night vision as in the Sodium (Yellow) streetlights you see, at least in Britain, it gives better night vision in misty/hazy (often usual at sea) conditions (that's why the Sodium streetlights on roads/motorways/autobahn)…
I always thought the UZO binocular (ones I have seen in photos) was normal size 7x50's…not these monsters?
They should have lens markings for range etc., if they are UZO bins…
They should also have fitting for mounting on the UZO…
In alarm dive could you imagine humping these down the bridge hatch of a U-boat…If you drop them you will kill the bloke below ;-)
These sound like off surface ship…especially with the as stated "5.5" flip up hollow tubes with drain holes in the bottom and port hole doors on the very front"…where they would be in position semi-permenantly, not as in the U-boat UZO which are only mounted when needed…in most U-boats…not too often…
Regards Harvey