longines 330 movt (valjoux 72), case ref 8224-1 produced in '68. ive also seen 8224-4 produced in '69 with slightly diff dial (12-hour chrono reg is also white) and hands (pointed instead of block) and later movt (longines 332/valjoux 726).

not 100% sure if the intended purpose of the timing bezel is for regatta-starts or scuba-diving. there were a handful of similar-cased longines chronographs with slightly different features, some with fixed tachymetric chapter-rings, one with a special purpose longines manufacture movement for timing precise sub-second splits, and others that i cant recall at the moment.

there was also a dual-crown "ultra chron" diver variant produced, as well. it featured a manufacture longines high-beat movement.