Submariner 5513/5517 — MilSub

Rolex 1520

Non-chronometerChronometerA watch or movement certified for timekeeping precision under a defined testing standard. The applicable certification depends on its maker and period; it is not the same as a chronograph. caliberCaliberThe designation of a watch movement, identifying its design or movement family. with a lower-cost regulator and balance springBalance springThe fine spiral spring that works with the balance wheel to form the movement’s oscillator.; replaced the 1530 in the 5513 late in the gilt era. Used in the military references.