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Hello Everyone!

Looking for assistance in locating a Seiko mainspring or a mainspring that would work with the 29C UT movement. From my understanding the movement is part of the 66B / 6620B family. I have a Seiko #401660 but have not been able to locate this spring by this number anywhere I've looked. I did do the manual calculations for the mainspring required which are as follows:

Length 351.50  mm

Height 1.33 mm

Thickness .09 mm

Any help would be appreciated. 

Ed... 

 

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