These revolvers are physically similar to U.S.-made model. Exception, barrel address reads "Address Col. Colt. London" and British proof-marks stamped on barrel and cylinder. There were 42,000 made between 1853 and 1857. They have their own serial number range #1-#42,000. There are two major variations of London Navy. Again, a serious purchaser would be well advised to seek qualified appraisal as fakes have been noted.