Omega Chronometre de Marine 4.19 MHz

Very nice time piece, next to an atomic clock back in the day as accurate as you can get. I like the fact you can change the standard batteries one at a time without stopping the clock. People might not be aware but you can probably still order copies of the test papers from Neuchatel Observatory. As it is a scientific instrument they will hold the original test certificate and for a small fee will make a handwritten copy I expect. I did that for my Marine Chronometer watch.