The Cartier Tank Must WSTA0056 is the green one — the star of the color-lacquer trio that made the Tank the most talked-about watch of 2021. Cartier stripped the dial of every numeral and marker, lacquered it in deep green, and matched it to a green strap, reviving the playful spirit of the original 1970s Les Must de Cartier. The result sold out almost instantly and turned a century-old design into the fashion watch of its moment.
Here is the thing every owner learns: on this reference, the strap is not an accessory — it is half the design. The factory green strap makes the watch. It is also leather, which means it creases, fades, and wears out with regular use. This guide covers the correct replacement size for the WSTA0056 and the most popular Helvetus options for it.
Cartier Tank Must WSTA0056 Strap Size and Fit
For the Cartier Tank Must WSTA0056:
- Model: Tank Must, large model
- Case size: 33.7 mm x 25.5 mm, thickness 6.6 mm, steel
- Dial: green lacquered, marker-free, polished steel sword hands
- Attachment: standard spring bars
- Strap width at the case: 19 mm
This means the watch requires a 19mm strap. When ordering, simply select the 19mm option on the product page.
Proportions matter on a dial this minimal — the strap needs clean lines and the correct taper to preserve the Tank silhouette. Helvetus Tank straps are cut specifically for Cartier Tank cases and are compatible with your original Cartier buckle, so the hardware stays and only the leather changes.
The Watch That Is Its Strap
The monochrome Musts work because of total commitment: green dial, green strap, nothing else. Which makes strap condition unusually visible on this reference — a tired, creased strap dulls the whole effect in a way it never would on a silver-dial Tank.
Owners of the WSTA0056 tend to solve this in one of two ways. The first is the like-for-like refresh: a new green strap that restores day-one intensity. The second is the wardrobe approach: keep the green for its signature look, and add a contrast strap that turns the same watch into something entirely different for evenings and office days. Both take two minutes with spring bars.
The Best Straps for the Cartier Tank Must WSTA0056
Helvetus offers leather and crocodile straps cut for Cartier Tank models, including the Tank Must. You can browse every compatible option here: Cartier Tank Strap Collection.
Below are the most popular choices among owners of this reference, matched to its green lacquered dial and steel case.
Green Leather Strap
The reason most WSTA0056 owners land here. A fresh green strap brings back the exact monochrome look the watch was designed around — deep, saturated, and matched to the dial. When the factory strap starts showing its miles, this is the direct answer. Green Leather Strap for Cartier Tank
Black Crocodile Strap
The contrast play, and a spectacular one. Black crocodile frames the green lacquer like a jewel setting and takes the Must straight into evening territory — the strap that shows this watch was never just a summer fling. Black Crocodile Strap for Cartier Tank
Black Leather Strap
Smooth black leather is the everyday version of the same idea: it grounds the green dial, works with anything in the wardrobe, and lets the lacquer do all the talking during the week. Black Leather Strap for Cartier Tank
Brown Leather Strap
Green and brown are natural companions, and on the Must the pairing reads warm, organic, and quietly stylish — a softer alternative to black that suits the watch beautifully in autumn and daylight. Brown Leather Strap for Cartier Tank
Beyond these four, the collection includes further colors and finishes, all cut to the same Tank proportions.
Final Thoughts
The WSTA0056 proved that a hundred-year-old case could become the freshest watch in the room — but only with its strap in perfect condition. Keep a crisp 19mm green on it, add one contrast option, and the green Must stays exactly as striking as the day it sold out.
Helvetus is a leading name in aftermarket straps for luxury watches, trusted by more than 50,000 customers worldwide. Every Tank strap is cut for a precise fit on this case, and all orders ship free worldwide with no import costs.
Find the perfect strap for your Tank Must WSTA0056 in the Cartier Tank Strap Collection.
