WW2 Nazi box

A WW2 era leather box.

I found this little box at a rubbish dump in Exmouth, Devon. When I first saw it I thought what a lovely little box, super quality and excellent colour. Then upon closer inspection I saw the Carl Zeiss stamp and date with the Nazi eagle next to it. It is lined inside with a metal possibly tin or aluminium? I was told it might be a battery holder/case because of the metal lining however I am not sure a battery would be worthy of such a quality box? I am leaning towards it being a holder for some piece of optical equipment because of the Carl Zeiss stamp. Any feedback would be welcome and apologies for the poor photographs!