The Longines 636.1 watch movement, introduced during the period 1966-1970, is recognized for its impressive thinness, being the thinnest automatic movement at that time. It was eventually surpassed in thinness by the Piguet 71 movement in 2003, with a height of 2.4mm. Notably, the Longines 636.1 boasts a micro-rotor mechanism featuring four ball-bearings. Its Girocap combined settings contribute to its precise escapement wheel operation. Furthermore, the indirectly driven minute function allows for a low-profile design.