Very rare steel stainless Universal Geneva Tri-Compax cal 481 dated 1940s. 17 J , 18000 bph . 35mm . The most complicated chronograph at that moment and the icon of Universal Geneva ! All original n all function good !
https://www.timepiecechronicle.com/features/2016/8/3/reference-guide-universal-geneve-tri-compax-1944-to-1949