A WW2 era German stopwatch by Andreas Huber, Munchen.
These stopwatches were used on destroyers, cruisers and also U-boats to measure the time between firing and the  impact of the torpedo.
In working order with some signs of wear.
Enamel dial, bevelled glass and serial number to the inside.
Push fluted  button to the top to start, stop, reset and also to wind.
Measures 5cm diameter and 1cm deep.