The Certina 25-66M watch movement features jewel bearings for the barrel and an integrated automatic gear within the movement itself, as opposed to attaching it to a manual-wind calibre. This design enables a sturdy movement with a relatively large balance and low profile. The initial samples utilized ruby-ball bearings but did not include jewels for the automatic gears. This movement includes functions such as manual wind, sub-second, and date. It was prevalent during the approximate period of 1945.