The IWC 8541B watch movement, introduced in 1966, established itself as the thinnest automatic movement available at the time. It featured a micro-rotor mechanism with four ball-bearings, enabling a low profile design. Notably, the movement incorporated Girocap combined settings for the escapement wheel and an indirectly driven minute hand. It also possessed features such as an adjustable Stud Holder, offset center wheel, and Incabloc shock protection. The IWC 8541B movement was utilized from 1966 onward.