This has to be a very rare timepiece. Usually I see them in 35mm cases, but this one has appx. 37mm. The case is made of steel. Inside ticks a handwound caliber 89 which is very famous and was used a lot in IWC watches back in the 1950s and 1960s.
This timepiece can also be found in gold cases, or with automatic movements caliber 852 or 853. Most likely though with straight lugs and not with shark lugs. The shark lugs give it a very special look.