Ultra – mainsprings for all calibers

10 calibers with mainspring dimensions

Choose the caliber of your Ultra movement. The caliber page shows the mainspring dimensions and – if in stock – the matching mainspring from our shop.

Note: We have transcribed this information to the best of our knowledge from the Générale Ressorts mainspring catalogue (GR 2, 1974). All information has been carefully checked but is provided without guarantee. Please check yourself before fitting that the mainspring fits, in particular height, diameter, thickness and length.