Service history is known for the Royal Navy deck watches (top and left), courtesy of the Royal Maritime Museum in Greenwich. The lone Kriegsmarine navigation watch (bottom, also an Observatory prize winner) remains a mystery as the Hamburg depot was bombed during WWII and records destroyed. The two WWI veterans (top right - half chronometer, bottom right - one button chronograph) of the US Army Corps of Engineers have much of their hand-painted radium lume intact but, thankfully, recent testing shows there is virtually no residual radon. I love these tool watches!!