1500 — the most widely fitted of the 15xx automatics

In brief

No chronometer certificate came with the 1500. Underneath it is pure 15xx, 19,800 vibrations per hour and all, but Rolex held the official rating back for variants such as the 1560 and the 1570 — and the uncertified calibre ended up being the one it built in the greatest numbers.

Short history

When Rolex standardised on 19,800 vph across its automatic family in the 1960s and 1970s, it reserved official chronometer certification for particular sports and upper-tier references. The 1500 covered the rest: a large share of the standard-production Oyster Perpetuals of the period ran on it, uncertified but on exactly the same mechanical base.

Watches that used it

• Rolex Oyster Perpetual (standard-range references, without chronometer certification)