The WSTA0119 is the small Tank Must SolarBeat exactly as it leaves the boutique today: a slim steel case of 29.5 x 22 mm and just 6.6 mm thick, a silvered dial with Roman numerals, blued sword-shaped hands, the blue spinel cabochon in the beaded crown – and, notably, a black grained calfskin strap with a simple pin buckle. Real leather, from the factory. Underneath runs the photovoltaic SolarBeat movement that charges through the dial and simply never asks for a battery. It's the configuration most people actually buy – and gift – which makes one thing certain: sooner or later, that factory strap will need a successor. Here's the correct size for the WSTA0119 and the best leather to put on it.
Which Strap Size Fits the WSTA0119?
The Tank Must SolarBeat WSTA0119 takes a 16mm strap. On our product pages, simply select the 16mm option – that is the correct fit for the small 29.5 x 22 mm case.
Cartier has given the small SolarBeat a few reference numbers over the years, so here's the simple rule: every small model shares this same case – if yours measures 22 mm across, it takes 16mm, whatever the reference on your papers says. The Large SolarBeat models (25.5 mm across) take 19mm instead, and the XL automatic Tank Must takes 23mm.
Fitting takes a minute: the strap mounts on standard spring bars, and every Helvetus strap comes with its own buckle included, so nothing needs to be reused from the original.
A Quick Look at the WSTA0119
The small Tank has been the shape of an elegant gift for over a century – the 1917 silhouette, scaled to its most graceful proportions. The SolarBeat generation kept every line of it and quietly rebuilt what's underneath: light passes through fine perforations in the dial to feed the photovoltaic movement, and the watch runs for years with no winding and no battery anxiety. The WSTA0119 pairs that engine with a black grained calfskin strap – the current generation returned to genuine leather, and the watch feels all the more classic for it.
That grained calfskin is also the honest heart of this guide. On a small Tank there is no bracelet to fall back on; the strap is the watch's only wearing part. Leather lives an ordinary leather life – sun, skin, sleeves, and seasons all leave their mark – while the movement above it is engineered to outlast several straps without a service. In other words: a strap change isn't an "if" with this reference, it's a built-in part of ownership. The only question is whether you'll match the original or take the chance to make the watch your own.
Both answers are below.
The Best Straps for the Cartier Tank Must SolarBeat WSTA0119
Silvered dial, blued hands, the most gifted case Cartier makes – the small Tank rewards both faithful choices and personal ones. These are the picks that suit the WSTA0119 best.
1. Pink Leather – The Gift, Made Personal
The small SolarBeat is one of the most gifted watches in Cartier's lineup, and the pink leather strap for the Cartier Tank is what turns a beautiful present into something unmistakably yours. The soft blush tone flatters the slim case, sits beautifully next to bracelets and rings, and gives the silvered dial a warm, personal frame. For the watch that marks a birthday, a graduation, an anniversary – this is the strap that makes it feel chosen twice.
2. Black Grained Leather – The Factory Strap, Renewed
Cartier ships the WSTA0119 on black grained calfskin, and the black grained leather strap is that exact recipe in a fresh, premium cut – same color, same texture, same quiet elegance. When the original has served its years, this is the seamless replacement: the watch looks exactly as it did in the boutique window, just new again. The straightforward choice most owners start with.
3. Red Leather – The Must Tradition
When the Must line first appeared in the late 1970s, colored straps were its signature – and red was the color that defined it. The red leather strap revives that spirit on the newest small Tank: bold against the silvered dial, unmistakably Cartier in character, and a favorite choice among Tank owners who want their watch to carry a little history.
4. Blue Leather – The Signature Detail
Blued sword hands over the dial, a blue spinel in the crown – blue is the accent Cartier built into this watch, and the blue leather strap carries it across the wrist. Deep, refined, and effortlessly office-appropriate, it's the swap that looks like it came from the factory that way.
Want to browse further? The full strap collection for the Cartier Tank includes more colors and crocodile-textured options – all available in the 16mm fit for this reference.
Final Thoughts
The WSTA0119 will run on daylight for years on end – the strap is the one part of the story you get to write. Renew the factory look when its time comes, or give the small Tank a color of its own, and keep the watch doing what it does best: quietly keeping perfect time, powered by nothing at all.
Helvetus is one of the leading names in aftermarket straps for luxury watches, and our Tank straps are cut for these slim rectangular cases rather than adapted to them. Every order ships free worldwide with no import costs, returns are easy, and more than 50,000 watch owners around the world trust our straps on their timepieces. The sun takes care of the movement – the strap is yours.
