The example below is based on an UT6497 calibre, the form of the movement is altered to a tourneau shape and skeletonized. The vibrations per hour of the balance is 18000, which associates with early calibers predominantly pre- 1950's.

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Inclined view of bridge side of movement, the frequency of the balance is 18000 vibrations per hour.

All of the jewels are pushed (friction fitted) in the bridges. 

Diverse views of the piece