The WJTA0037 is the small Tank Louis Cartier with its case and beaded crown in 18K rose gold, set with 41 brilliant-cut diamonds totalling 0.47 carats. Underneath sits a silver-grained dial with black Roman numerals, a railway-track minute ring and blued-steel sword hands, driven by a hand-wound manufacture movement.
The case is 29.5 × 22 mm and 6.8 mm thick. Cartier delivers it on claret alligator with a rose gold ardillon buckle.
That size matters more than it sounds, because it changes what a strap can actually do. On a 22 mm-wide case there is not much surface area for a colour to make a statement — but there is more than enough for texture to catch light right next to the stones. On the small Tanks, texture does the work that colour does on the large ones.
Lug Width: the WJTA0037 takes a 16 mm strap
On the product page, select the 16 mm option.
The small Tank Louis case measures 29.5 × 22 mm and uses a 16 mm strap. That figure appears in exact-reference specification tables for the small Tank case, in the sizing charts of independent strap makers who list the Tank Small at 16 mm, and it is the size we stock for the model.
| Tank Louis model | Case | Strap |
|---|---|---|
| Small (WJTA0037) | 29.5 × 22 mm | 16 mm |
| Large | 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 large size as the WJTA0038. If that is the one on your wrist, order 19 mm.
Three things to get right:
- Standard spring bars. No proprietary fitting. A spring bar tool or our installation tool is enough.
- Tape the lugs. Rose gold is soft, and on this reference the stones run right along the edges of the case. A slipped tool near a diamond setting is the most expensive mistake in this article, and masking tape costs nothing.
- Rose gold buckle. Our Tank straps are 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 hardware sitting in plain view beside the case.
Crocodile is available at this size, and that is the point
This is the practical reason the small Tanks are more interesting to strap than the large ones.
Our Tank crocodile straps are cut in 14, 15, 16 and 17 mm — which means a 16 mm case can have them and a 19 mm case cannot. On a diamond-set watch that is not a small detail. Cartier fits this reference with alligator, and exotic leather is the only material that answers a set case in the same register: fine, dense scales reflecting light beside the stones instead of sitting flat next to them.
A smooth calf strap on a diamond Tank is not wrong. It is just quieter, and on a 22 mm case the difference between quiet and considered is mostly texture.
The four best straps for the WJTA0037
1. Brown crocodile — texture that matches the register
Brown Crocodile Strap for Cartier Tank
Warm brown and rose gold share a temperature, so brown lets the case look rich rather than bright — and in crocodile it also gives the watch a second textured surface to play against the diamonds. At 16 mm the scales are small and tight, which suits a delicate case perfectly; the same skin on a 20 mm strap would look far more assertive. This is the most complete-looking way to wear the reference, and the closest in feel to what Cartier fits at the factory.
2. Red leather — the colour Cartier chose
Red Leather Strap for Cartier Tank
Claret is not an accident. Cartier could have shipped this watch on black or brown and instead picked a deep wine red, which tells you the intended register is jewellery rather than conservative dress watch. Red is warm enough to belong with rose gold, dark enough to frame the stones, and far enough from brown to look like a decision. Our red is the closest tone in the Tank range to the factory strap.
3. Black crocodile — for the evening, and for the stones
Black Crocodile Strap for Cartier Tank
Contrast is what makes set stones catch light, and black is the highest-contrast option there is. In crocodile it keeps the formality of black without the flatness — the scales stop a small black strap looking like a plain band under a valuable case. This is the configuration for evenings and for anywhere the diamonds are meant to be noticed.
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 pairings in modern jewellery. It cools a warm case without fighting it and it is the least formal of the four — the version you wear during the day without the watch announcing what it cost.
Every colour and width is in the Cartier Tank, Tank Louis, Américaine, Solo and Must strap collection.
Fit, in one line
Order 16 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
- Cartier Tank Solo WSTA0028 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 over 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, and 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 6.8 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 and crocodile straps are covered for one year; our rubber straps carry a lifetime warranty.
