Hi everyone, this is my first post here.
A good friend has asked me to restore an important family treasure. This IWC is about 38mm. Serial number 741143. It has a patent number of 55231. I think the old broken mainspring in it is an earlier incorrect replacement. Can anyone tell me the caliber of this movement and the size (width, strength and length) of the correct mainspring for this watch? Also, if no replacement is available from my usual sources can I obtain a replacement mainspring directly from IWC?
Thank you in advance for your assistance.
Greg
