Preserved in good and original overall condition, the present chronograph is fitted with the caliber 12.68 Z movement with flyback or “retour-en-vol” system. It furthermore stands out by the very attractive two-tone silvered dial with blue timing scales.

Longines was always renowned for its chronograph watches and the flyback mechanism itself was developed and patented by the company in the 1930s. The flyback function was particularly useful for aviators as it allows the reset mechanism to take place while the chronograph is running, therefore consecutive events can be timed very precisely. The chronograph does not have to be started, stopped and reset in the usual way, with the flyback chronograph, both the chronograph hand and minute register hand run constantly and are immediately reset to zero at each press of the button.

Similar watches with caliber 12.68 Z movements are prominently described and illustrated in: Longines Watches, John Goldberger, Damiani, 2006, pp. 126-150.