Hello everyone, I purchased this PW some 2yrs ago now and it has sat as I know nothing about Omegas thou own a number of them. I set out on a search to run into a few road blocks. serial number was easy enough to find out about, however Model number to get parts for it. Serial Number is 4591147 Production date of 1915. Run Id 21, G21 M21 U21. the balance is fine thou the main spring is stuffed, and need to replace that once I know the model. many thanks Francis