The Santos Skeleton is the one Cartier where the strap is not only under the watch. It is in it.
Take the movement out of a normal dial's way and what fills the gaps is whatever sits behind the case — your wrist, and the strap wrapped around it. On the WHSA0007 the skeletonised bridges form the Roman numerals themselves, with nothing but open space between them, so the colour you choose reads straight through the middle of the watch. Change the strap and the dial changes with it.
That is a decision no other Cartier asks you to make. Everything below is about getting it right.
Lug Width: the WHSA0007 takes a 21 mm strap
On the product page, select the 21 mm option.
The WHSA0007 is the large model — a 39.8 mm steel case, 9.08 mm thick — and the large Santos takes a 21 mm strap. The medium takes 19 mm. That is the only sizing decision on this watch, and getting it wrong is the most common Santos ordering mistake there is.
| Santos model | Case | Strap |
|---|---|---|
| Large (WHSA0007) | 39.8 mm | 21 mm |
| Medium | 35.1 mm | 19 mm |
QuickSwitch means no tools, ever
Cartier built this watch to have its strap changed. It ships with two: the steel SmartLink bracelet and an alligator strap, both fitted with the QuickSwitch system, which releases with a press underneath the strap end and no tool at all.
Our Santos straps carry the same QuickSwitch fitting, so they click into the case exactly like the originals. That also means a generic 21 mm strap is not an option here — without the Cartier interface it has nothing to attach to. The fitting is the product.
Practically, a swap takes about ten seconds. On a watch that already came with two straps, adding a third and fourth is the obvious move.
Why strap colour does more work on a skeleton
On a solid dial the strap is an accessory. On an openworked one it is a background, and backgrounds behave differently.
Dark straps give you contrast. Black behind the movement pushes the skeletonised bridges forward, so the Roman numerals read as crisp shapes and the finishing on the bridges stands out. It is the setting that makes the watch look most architectural, and it is the reason most openworked watches are photographed on black.
Light and warm straps soften it. Brown or a lighter tone fills the openwork with something closer to skin colour, which makes the movement blend into the wrist and the whole watch look quieter. Less graphic, more wearable — some owners much prefer it.
Colour reads twice. A blue strap on this watch shows at the lugs and through the dial, so a colour that would be a small accent on a Ballon Bleu becomes half the watch here. Worth knowing before you order.
None of these are wrong. But they are genuinely different watches, and it is worth owning at least two.
The four best straps for the WHSA0007
1. Black rubber — the sharpest version, and the most wearable
Black Rubber Strap for Cartier Santos
Two things at once. Visually, black behind an openworked movement is maximum contrast: the bridges, the numerals and the blued hands all read at a glance instead of competing with what is behind them. Practically, the WHSA0007 is water-resistant to 100 metres, and rubber is what lets you use that — this is a skeleton watch you can wear in the summer, on holiday, and around water without a second thought.
Our rubber straps carry a lifetime warranty, so it is also a one-time purchase.
2. Blue leather — the colour the watch already has
Blue Leather Strap for Cartier Santos
The hands are blued steel, and on an open dial they are one of very few coloured elements you have. A blue strap picks them up and, because it also shows through the movement, turns the whole watch blue rather than just the tips of two hands. It is the most striking thing you can do to this reference and still look deliberate.
3. Brown leather — the quiet, warm version
Brown Leather Strap for Cartier Santos
Brown does the opposite of black: it fills the openwork with a warm tone close to the wrist itself, so the movement stops shouting and the watch reads as a dress piece rather than a technical one. On a 39.8 mm steel case it is the most understated way to wear something this complicated, and it is the strap that makes the Skeleton work with a jacket.
4. Black leather — dress, without the sport
Black Leather Strap for Cartier Santos
The same contrast as the rubber with a formal finish instead of a sporty one. This is the version for evenings and for anywhere the rubber would look out of place, and it is the strap that most closely mirrors the alligator Cartier supplies in the box — without you having to wear out the original.
See every colour and material in the Cartier Santos QuickSwitch strap collection.
Fit, in one line
Order 21 mm with the QuickSwitch fitting, and click it in — no tools.
More Cartier strap guides
- Cartier Santos de Cartier WSSA0018 Strap Guide — the large steel Santos, same 21 mm fit
- Cartier Santos de Cartier W2SA0016 Strap Guide
- All Cartier strap guides
Keep the bracelet in the box
Helvetus straps are made for one watch at a time. Our Santos straps carry the QuickSwitch fitting in 19 mm and 21 mm, so they lock into the case the way the originals do — and every day the steel bracelet spends in its box is a day it is not collecting hairlines on the polished links.
More than 50,000 customers worldwide, free shipping and free returns, and no import costs on any order, anywhere. Rubber straps carry a lifetime warranty; leather is covered for one year.
