Rolex · Cosmograph Daytona
Rolex Cosmograph Daytona 126500LN: specifications and what to check
A chronograph rated to 100 metres, not 300, with a tachymetric scale moulded into the ceramic bezel rather than printed on it. The calibre 4131 and its 72 hours are what separate this reference from its predecessor.
Reference 126500LN · specifications read from the manufacturer on 2026-09-22 · listed as current
Specifications
As published by Rolex. A field the manufacturer does not state is left out rather than filled in.
- Case
- Oyster, 40 mm, Oystersteel. Monobloc middle case, screw-down case back and winding crown
- Diameter
- 40 mm
- Water resistance
- Waterproof to 100 metres / 330 feet
- Crystal
- Scratch-resistant sapphire
- Bezel
- Black monobloc Cerachrom bezel in ceramic with moulded tachymetric scale
- Dial
- White, black counter rings, with highly legible Chromalight display with long-lasting blue luminescence
- Case back
- Screw-down
- Crown
- Screw-down, Triplock triple waterproofness system
- Bracelet
- Oyster, three-piece solid links, Oystersteel
- Clasp
- Folding Oysterlock safety clasp with Easylink 5 mm comfort extension link
Movement
- Calibre
- Calibre 4131, manufacture Rolex
- Type
- Perpetual, mechanical chronograph, self-winding; bidirectional self-winding via Perpetual rotor
- Power reserve
- Approximately 72 hours
- Certification
- Superlative Chronometer (official chronometer certification + Rolex certification after casing)
- Notes
- Precision −2/+2 sec/day after casing. Small seconds at 6 o'clock, 30-minute counter at 3, 12-hour counter at 9. Paramagnetic blue Parachrom hairspring with Paraflex shock absorbers.
What to check before you buy
- Examine the tachymetric scale closely. Rolex moulds it into the ceramic rather than printing it, so the markings are part of the bezel — anything that looks applied, painted or shallow is not right.
- Run the chronograph through start, stop and reset several times and confirm all three counters return precisely to zero. A hand that stops short or overshoots is a service item, not a setting quirk.
- Unscrew and re-seat both pushers as well as the crown. On a screw-down chronograph the pushers are part of the seal, and cross-threaded pushers are common on watches used by people in a hurry.
- Confirm the calibre is 4131 and not the earlier 4130. The 72-hour reserve belongs to the newer movement, and the reference changed with it — papers and reference must agree.
- Remember this is rated to 100 metres, not the 300 of the dive references. It shares the Oyster case language but not the depth rating, and a buyer assuming otherwise has been misled.
A scale that is part of the bezel
The tachymetric scale here is moulded into the monobloc Cerachrom bezel, not printed onto it. That is a manufacturing distinction with a practical consequence: the numbers cannot wear off, because they are not sitting on the surface.
For inspection it gives you something definite to look at. Correct markings sit in the ceramic with depth and consistent edges. Anything that reads as applied, painted, or shallow under magnification deserves a much closer look at the rest of the watch.
Seventy-two hours, and why the number matters
The calibre 4131 carries approximately 72 hours of reserve, where the movement it replaced held around two days. Rolex changed the reference number when it changed the movement, which means the two are tied together.
This is the same trap as on the Submariner: a listing written from memory will happily describe an older watch using current figures. Check the reference, check the papers, and check they agree with the calibre being claimed. On a watch at this level the difference is not academic.
A chronograph is a set of mechanisms to exercise
Do not accept a Daytona on a glance at the dial. Start it, stop it, reset it, and do that several times. All three counters — centre seconds, the 30-minute register at 3, the 12-hour register at 9 — should return exactly to zero every time.
Then deal with the pushers. They screw down, they form part of the case seal, and they are handled constantly by owners who want to time something. Unscrew and re-seat each one and feel for clean threads. A cross-threaded pusher is both a water-resistance problem and an expensive repair.
One hundred metres, despite appearances
This carries the Oyster case, the Triplock crown, and the screw-down back — the whole vocabulary of a Rolex dive watch — and is rated to 100 metres.
That is entirely adequate for ordinary life and emphatically not a diving specification. It is worth saying plainly at the point of sale, because the case language invites the wrong assumption and the correction is much cheaper before money changes hands than after.
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Sources
Not affiliated with Rolex. Specifications are read from the manufacturer's own published documentation on the date shown and may change; the manufacturer's current documentation governs.