The angular, integrated bracelet steel case of the Rolex ref. 1530 was originally designed for the Oysterquartz. In 1975, before introducing the Oysterquartz, Rolex produced a limited number of ref. 1530, housing the chronometer-certified, caliber 1570. This model was discontinued shortly-after, in 1977, upon introduction of Rolex's quartz calibre. It’s estimated that less than 1,500 examples of the ref. 1530 were produced.