The Sea King Twin Power features the Cal. 269 of the 250/251 movement-family, which was originally introduced and patented in 1962, and which has a height of only 2.95 mm. With this movement, Favre-Leuba revolutionized the series production of extra-flat watches with a centered second hand: the design with two barrels makes it possible to use components with conventional dimensions and place the center second hand on the same level as the barrels. With this construction, the designers were able to reduce the height of the caliber significantly.
The solid movement has a power reserve of 50 hours and outstanding stability. It was available in different versions, with or without a calendar function, and was later manufactured as an automatic version and used in a wide range of watch models.