Outside diameter is 20 and face is 15 across. Movement is not the bichronous original but a contemporary replacement and the original braided fabric power cord has been replaced. The only missing component is the round fiberboard back but it is not needed for function or display.
I have seen several pictures of WWII-era shops and factories and they all had one of these high up on the wall. You will be hard pressed to find another such clock in this condition and it also has interest as a military artifact. Army Air Force 20 24 Hour Hammond Postal Telegraph Wall Clock" is in sale since Saturday, June 8, 2019.
This item is in the category "Collectibles\Clocks\Vintage (1930-69)\Wall". The seller is "2camsam" and is located in Clearfield, Utah. This item can be shipped to United States.