The Reason
The unusual balance design (described below) which is often seen in horological theory but less so in the metal.
The movement was approximately 26mm in diameter and 3.6mm tall, with 17 jewels and and a frequency of 18000 A/h. The power reserve was for 48 hours. There were hundreds of thousands of these movements made and used by different brands with various differences in finishing, balances and shock protection. This particular version signed by 'Wyler' made in the 1950'2 has no shock protection on the balance pivots but has balance arms made in an 'S' form which theoretically would be flexible when the watch received an impact protecting the pivots from being bent or broken.
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