The Cartier Tank Must WSTA0040 is the Tank most men actually buy. When Cartier revived the Must line in 2021, the extra-large model was the one that mattered: the only automatic in the range, a proper 41 x 31 mm presence on the wrist, a date at 6 o'clock, and a case just 8.4 mm thin. It became an instant staple — and since every Tank lives on a leather strap, every WSTA0040 owner ends up in the same place eventually: the original strap ages, and the watch deserves better than a tired band.
This guide explains the correct strap size for the WSTA0040 and the most popular Helvetus strap options for this model.
Cartier Tank Must WSTA0040 Strap Size and Fit
Sizing first. For the Cartier Tank Must WSTA0040:
- Model: Tank Must, extra-large model
- Case size: 41 mm x 31 mm, rectangular
- Attachment: spring bars
- Strap width at the case: 23 mm
This means the watch requires a 23mm strap. When ordering, simply select the 23mm option on the product page.
A note on the fitting: Cartier ships the WSTA0040 with its own tool-free strap fitting, but the lugs accept any properly made 23mm strap. Helvetus Tank straps come with spring bars for a secure hold, and they are compatible with the original Cartier folding clasp — so you can keep the buckle you already love.
Shape matters as much as width here. The Tank's slim rectangular case demands a strap with clean, straight proportions; a generic strap sits awkwardly against those famous vertical brancards. Every Helvetus Tank strap is cut to follow the lines of the case.
A Century of Design, Built for Leather
The Tank goes back to 1917, when Louis Cartier drew a case inspired by the top-down silhouette of the first military tanks. More than a hundred years later it remains the definitive rectangular watch. The "Must" name nods to the famous Les Must de Cartier era of the 1970s, and the 2021 revival brought that accessible spirit back — with the XL as its most serious expression.
Because the Tank has never pretended to be anything but a strap watch, the strap carries half the design. Swap it, and you effectively own a different Tank: formal on crocodile, vintage on brown, unmistakably current on green. Many owners keep two or three in rotation and change them with the season or the occasion.
The Best Straps for the Cartier Tank Must WSTA0040
Helvetus offers leather and crocodile straps cut for Cartier Tank models, including the Tank Must XL. 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 silvered flinqué dial, blued hands, and steel case.
Black Leather Strap
The WSTA0040 left the boutique on black grained calfskin, and black leather remains the definitive Tank look. It frames the silvered dial, sharpens the Roman numerals, and works everywhere from the office to a wedding. If you replace like for like, this is the one. Black Leather Strap for Cartier Tank
Black Crocodile Strap
For a step up in formality, black crocodile gives the Tank Must the full dress-watch treatment. The scale texture adds depth that smooth leather can't match, and it is the strap this case was drawn for a century ago. Black Crocodile Strap for Cartier Tank
Brown Leather Strap
Brown warms the silver dial beautifully and gives the WSTA0040 a softer, more vintage character. It is one of the most popular choices for daily wear — smart with a jacket, relaxed with everything else. Brown Leather Strap for Cartier Tank
Green Leather Strap
Green on a silver-dial Tank is the modern combination, and it suits the Must generation perfectly. It keeps the watch elegant while making it feel unmistakably current — the pick for owners who want their Tank noticed. Green 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 WSTA0040 earned its place as the modern men's Tank by getting everything right: the size, the movement, the thinness. Keep the strap as sharp as the case, and it will outdress watches at five times the price.
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 WSTA0040 in the Cartier Tank Strap Collection.
