Cartier could have sent this watch out on black alligator. It sent it out on claret — a deep wine red.
That choice tells you how the WJTA0038 is meant to be read. This is the large Tank Louis Cartier with its case and beaded crown in 18K rose gold, set with 41 brilliant-cut diamonds totalling around 0.66 carats, over a silver-grained dial with black Roman numerals and blued-steel sword hands. Hand-wound, 33.7 × 25.5 mm, 6.6 mm thin.
It is not a conservative dress watch with some stones added. It is jewellery that happens to tell the time, and Cartier picked a strap colour that says so.
Lug Width: the WJTA0038 takes a 19 mm strap
On the product page, select the 19 mm option.
The large Tank Louis case measures 33.7 × 25.5 mm and uses a 19 mm strap — the same as every other large Tank Louis and large Tank Must. The figure is confirmed by independent strap makers listing the large Tank at 19 mm, by exact-reference sizing charts, and by our own live guide for the large steel Tank Must.
| Tank Louis model | Case | Strap |
|---|---|---|
| Small | 29.5 × 22 mm | 16 mm |
| Large (WJTA0038) | 33.7 × 25.5 mm | 19 mm |
| Newer automatic large model | 38.1 × 27.75 mm | A different case — do not assume 19 mm |
Cartier makes the same watch in the small size as the WJTA0037. If that is the one on your wrist, order 16 mm.
Three things to get right:
- Standard spring bars. No proprietary fitting. A spring bar tool or our installation tool does it.
- Tape the lugs first. Gold is soft and this case is set with stones along its edges. A slipped tool near a diamond-set case is the most expensive mistake in this article.
- Rose gold buckle. Every Helvetus Tank strap is ordered with a buckle finish, and the factory buckle here is an 18K rose gold ardillon. Gold and silver are for the yellow gold and white gold Tanks. On this one, rose gold — it is the only piece of hardware that sits in plain view beside the case, and a mismatch is instantly visible in photographs.
Warm gold and white diamonds pull in opposite directions
This is what makes the WJTA0038 more interesting to strap than a plain gold Tank.
Rose gold is the warmest metal Cartier uses. Diamonds throw cold white light. The watch already contains both, which means the strap is not just choosing a colour — it is deciding which of those two things the watch leans into.
Warm straps side with the gold. Reds and browns push the case forward, the stones become texture rather than the point, and the watch reads as rich and soft. This is where Cartier put it.
Dark straps side with the diamonds. Maximum contrast is what makes stones catch light, so black turns the sparkle up and the warmth down. The same watch reads sharper, more formal, more like jewellery for the evening.
Neither is more correct. But a diamond case has one setting — on — so the strap is the only thing that moves. It is worth having both.
The four best straps for the WJTA0038
1. Red leather — the register Cartier chose
Red Leather Strap for Cartier Tank
Claret and rose gold is a deliberate combination: wine red is warm enough to belong to the same family as the case, dark enough to frame the diamonds, and far enough from brown to look like a decision rather than a default. It is the closest tone in our Tank range to the strap this watch left the boutique on, and paired with the rose gold buckle it puts the reference back exactly where Cartier intended. If you replace the original with one strap, replace it with this.
2. Brown leather — the version you wear without thinking
Brown Leather Strap for Cartier Tank
Brown is the quiet member of the warm family. It agrees with rose gold completely, softens the whole watch, and takes the diamonds down from statement to detail — which is exactly what a lot of owners want on an ordinary day. This is the strap that makes a $25,000 jewellery watch wearable at lunch, and for most people it ends up being the one it lives on.
3. Black leather — for the evening, and for the stones
Black Leather Strap for Cartier Tank
Black is the only true neutral that does not join the warm family, and that is precisely why it works. Against black, rose gold looks brighter and the diamonds look harder — maximum contrast is what makes a set case sparkle. This is the most formal configuration available and the one to reach for when the watch is going somewhere the diamonds are supposed to be seen.
4. Blue leather — the cool counterweight
Blue Leather Strap for Cartier Tank
The hands are blued steel, so blue is already on the watch — and blue against rose gold has become one of the most reliable combinations in modern jewellery and watchmaking. It cools the case without fighting it, and it is the most contemporary of the four. The choice for an owner who wants the watch to look current rather than inherited.
Every colour and width is in the Cartier Tank, Tank Louis, Américaine, Solo and Must strap collection.
Fit, in one line
Order 19 mm with the rose gold buckle, and tape the lugs before you fit it.
More Cartier strap guides
- Cartier Tank Must WSTA0041 Strap Guide — the large steel Tank, same 19 mm fit
- Cartier Tank Must Blue WSTA0055 Strap Guide
- All Cartier strap guides
The only part of this watch that ages
A Tank Louis has never come on a bracelet — not this reference, not any of them, in more than a century. The strap is part of the design rather than an accessory to it, and on a diamond-set case it is also the only component that will ever need replacing. Alligator creases at the lug ends and darkens where it meets the skin; against rose gold and stones, that shows sooner than it would on steel.
Helvetus straps are cut for the Tank case in every width from 14 mm to 25 mm, slim enough for a 6.6 mm case, and shaped so the leather meets the brancards without the gap a generic strap always leaves.
More than 50,000 customers worldwide, free shipping and free returns, and no import costs on any order, anywhere. Leather straps are covered for one year; our rubber straps carry a lifetime warranty.
