WWII US Navy 12/24 Hour Military Clock by Chelsea Clock, Boston-This is produced in black bakelite. It registers 12- and 24-hour time and works well. We include a reproduction key so you can wind it and use it as you please. The face says "Chelsea Clock Co, Boston" followed by "U.S. Navy, Ser. No 40646E". The movement has the serial number 337655 which indicates production some time in 1941. Overall good condition!