

If you are going to wear it a lot you should get it serviced by a competent watchmaker.

When you close it be sure you press the button when you close the cover, never "snap" it shut. The chain or thong reduces the liklihood of dropping your watch, which will not do it any good. If you wear it wear it on a chain or thing and better get put it in a leather bag when you put it in yorr pocket. Gubelin sold very fine watches and this is pretty much what one would expect from them. I see what looks like one mark on the body in the movement view, near about 11 o'clock. If the markes are different let us know since they indicate a later date. These are very small so you have to look closely. If 14k the mark will probably be a squirrel. These should be on the pendant on each cover, on the ring and on the body of the case usually under the inner cover. If so look for a very small woman's head punched in several places. Your watch almost certainly is hallmarked. Movements finished in nickel are usually for the US market but the regulator is marked "A and R" as well as "F and S". This is an ultra flat model which also makes the 1910 to 1930 period a strong possibility. It is marked 21 Rubis or 21 jewels which is a very high jewel count for a Swiss watch of this size and period. Watches like this were available from 1910 to the 1950 's but 1920 is far more likley than 1950. Several makers used this basic movement so its hard to tell who the actual maker was. It looks like a very high grade movement. Gubelin was and is a high end retailer and they may be able to give you some information.
