Journal · Reference notes
How to read a reference number
126610LN, 15500ST, 5711/1A-010 — what each part means, and how to tell at a glance what you are being offered.
From the bench, Los Angeles · · 2 min read
Why it is worth ten minutes
A reference number is the only part of a watch's description that cannot be marketing. Learn to read one and you can tell case metal, bezel material and often the generation of the movement before anybody tells you anything — including whether the words in a listing match the number beside them.
Rolex: five or six digits, then letters for the materials
Take 126610LN. The first digits are the model family and generation: 126610 is the current Submariner Date, where 116610 was the one before it and 16610 the one before that. A leading 1 followed by 2 marks the generation that brought the newer calibre and the wider bracelet.
The letters are the materials, in French. LN is lunette noire, a black bezel; LV is lunette verte, green — the Kermit and the Hulk. BLNR is bleu-noir, the blue-and-black GMT the internet calls Batman. BLRO is bleu-rouge, the Pepsi. On a Datejust, a trailing 0002 or 0008 is the dial and hour markers rather than anything structural.
Two digits in the middle carry the metal: 0 is steel, 1 yellow-gold Rolesor, 3 white gold, 5 Everose. That is how 126334 tells you white Rolesor without a single adjective.
Audemars Piguet: the case, then the bracelet, then the dial
15500ST.OO.1220ST.03 looks worse than it is. 15500 is the model: the 41 mm Royal Oak Selfwinding that replaced the 15400. ST is the case metal — stainless; OR is rose gold, BC ceramic. OO is a separator and means nothing at all.
1220ST is the bracelet, in the same metal. The final .03 is the dial: 01 silver-toned, 02 black, 03 blue. So the whole string reads 41 mm Royal Oak, steel case, steel bracelet, blue dial — which is exactly how it is listed here.
Patek Philippe: model, then execution, then dial
5711/1A-010 breaks at the slash. 5711 is the Nautilus. /1 means it comes on a bracelet rather than a strap. A is steel — R rose gold, G white gold, P platinum. -010 is the dial: 010 is the blue-black gradient, 011 white, 014 olive green.
Which is why 5711/1A-014 and 5711/1R-001 are the same watch in different clothes, and why an Aquanaut 5167A-001 is the steel one on a rubber strap.
What to do with this
Read the number in any listing, then read the description, and see whether they agree. A page offering a rose gold 5711/1A has contradicted itself in eight characters. Every reference on this site is printed on its own page and repeated in the lot number we file it under, so you can check one against the other in a second — and so can we, in writing, before anything is dispatched.
— The concierge desk, United Luxury
