The Felsa 410 watch movement, introduced around 1972, is recognized for being one of the thinnest automatic movements at that time. It remained unrivaled in terms of slimness until the year 2003, only surpassed by the Piguet 71 movement with a comparable thickness of 2.4mm. This remarkable movement incorporates a micro-rotor mechanism, utilizing four ball-bearings to ensure smooth operation. Notably, the Universal 2-66 movement features a unique combination of settings, including an oil aperture for the escapement wheel. Additionally, the indirectly driven minute function contributes to its low-profile design. The movement was used approximately from 1974, with further details regarding its functionalities available.