British WW2 RAF/ Air Ministry 6B/ 221 Stopwatch

In a very good condition a British (AM marked) RAF 6B/221 stopwatch. The watch would have been used in aircrafts such as the Lancaster bomber and was used for navigational purposes and for accurate timings during a bombing run. It would also act as a useful backup for the pilot as a timer in the event that other instruments were put out of action. It appears to be in working order but sold as seen as a collectors item only. A very decorative piecie for display.