![Omega® Miscellaneous Case Parts, Crown Nut, calibres: 640, steel](http://perrinwatchparts.com/cdn/shop/files/no_image_available_722cd15a-c704-4494-9d38-e9078dc0b67c_800x800.webp?v=1706822441)
Omega® Miscellaneous Case Parts, Crown Nut, calibres: 640, steel
steel nut (slotted) for Omega® caliber 640 back wind, diameter of nut is 3.80 mm
* H. & W. Perrin Company Limited is independent of and not affiliated with or sponsored by Omega®. Omega® warranty does not apply to parts supplied by H. & W. Perrin Company Limited. Using generic parts may devalue your watch.