Shown here is lowest earliest serial number I have seen on Gruen Verithin. Movement marked only Swiss, Verithin, adjusted, 122551. Looks a little like an Aeby job, not Gruen, but inferior quality to Aeby Madretsches that have numbers starting 125k. Lowest I have seen is 126k on Mad. 0 size 1907 engraved gift. Because of low number I am inclined to think it is first production design of the famous Verithin. Case is odd with hinge front and double hinge back. Permanent Gold Fill marked. Dial seen on other early Verithins. Why hinge the front glass?