Peep Show: A Roundup of Our Favorite See-Through Timepieces

For many watch enthusiasts, the ability to observe a mechanical movement in motion, either through cutaways, skeletonization, or a sapphire crystal dial, is a major draw. In fact, some demand full transparency, which has led to major innovations in clear sapphire crystal cases over the last decade.

Sapphire has a score of 9 on the Mohs hardness scale, making it the third-hardest natural mineral after diamond (10) and moissanite (9.5). The “sapphire” used in watch cases is actually a synthetic material; however, it is equally hard. That makes it extremely difficult to mill.

Thus, sapphire crystal requires diamond-tipped machines to cut and sculpt. Even then, its highly brittle nature makes this transparent material prone to shattering while being shaped. All in all, working with sapphire crystal is costly, complex, and incredibly time-consuming.
Still, brands have made significant strides in shaping, tinting, and pushing the boundaries of design with this material. Here’s a window on some of the best new (and newish) clear cases.

Bell & Ross BR-01 Cyber Skull Sapphire

Bell & Ross are best known for their aviation-influenced watches, but this fully translucent BR 01 Cyber Skull Sapphire from the French brand’s signature Cyber Skull collection is a true flight of fancy.

To express all the seductive power of the skull, Bell & Ross utilized a 45mm case made of sapphire. As a result, the skull and crossbones appear to float inside this sapphire sandwich. The skull is also an integral part of the movement, highlighting technical features like the balance at 12 o’clock and the barrel at 6 o’clock, while the crossbones form some of the movement’s bridges.

It’s a big watch, granted, but to reinforce this “floating” sensation, the brand’s logo and hour markers are printed on the inside of the crystal. Moreover, to make the overall look feel even lighter, Bell & Ross has equipped the watch with a translucent soft silicone strap, which is closed by a polished and satin-finished steel pin buckle.

Hublot Big Bang Sapphire Sky Blue

Rarity is another reason why collectors love sapphire-cased watches. In fact, very few brands have the machinery (and savoir-faire) to manufacture these marvels. Hublot is one of them.

It’s been ten years since the brand launched its first sapphire Big Bang. Since then, they’ve innovated with a whole rainbow of colors and audacious complications like the MP-10 Tourbillon Weight Energy System Sapphire.

In July, Hublot dropped the Big Bang Sapphire Sky Blue. This new version comes in a fully polished 44mm sapphire crystal case, which is water-resistant up to 50 meters. Its matte sky-blue skeleton dial and matching movement bridges let you see almost everything, including the running seconds at 9 o’clock and a power reserve at 6 o’clock.

The Big Bang Sapphire Sky Blue is powered by the HUB1201 Manufacture movement, a fully skeletonized, manually wound calibre that features a Meccano-inspired design that reveals almost every part of its mechanics. This movement can also be seen through the sapphire caseback.

Finally, while the sky-blue rubber strap is opaque, that’s okay. It keeps the color theme going.

Behrens x Konstantin Chaykin Ace of Hearts

Last year, Russian watchmaker Konstantin Chaykin’s paired up with Chinese brand Behrens to create the Ace of Hearts. This watch referenced both Chaykin’s signature Joker character and one of Behrens’ signature trapezoidal cases. At the time, much was made of the watch’s visual uniqueness, but let’s talk about what wasn’t visible.

The collection was made up of four different editions, including one in and two limited editions in either clear blue or pink sapphire. In both versions, the Ace of Hearts’ mechanism is part of the design, with two “eyes” on the dial displaying the hours and minutes and a red, heart-shaped seconds hand powered by Behrens’ patented mechanism.

A separate power-reserve indicator placed at 12 o’clock keeps you informed of the movement’s full 46-hour autonomy. And all of this information floats within a see-through frame. It’s fun and haunting at the same time!

Cvstos Challenge Purity Ti Comp

Color is another reason sapphire cases are so compelling. This summer, indie maison Cvstos added four new transparent hues to its Challenge Purity Ti Comp collection.

Available in 10 different colorways, all limited to 10 pieces each, these palettes make the 41 x 53.7mm, tonneau-shaped cases feel more like polished jewels – an illusion that is highlighted by its time-only display. The hand-wound, Cvstos CVS610, manual-winding titanium movement is just as elemental, and it helps reduce the weight of the sapphire.

Lastly, the visual lightness is matched by the ergonomic shape of the crystal case and your choice of either a rubber or Cordura strap.

Zenith Defy Zero G Sapphire

Okay, it’s been almost a year since Zenith dropped the Defy Zero G Sapphire, but it would seem to, ahem, defy reason to leave it off the list.

The main attraction of the Defy Zero G is its Gravity Control System – an innovation that takes the watch’s regulating organ and mounts it on a miniature gimbal. It sounds like a tourbillon, but it’s not.

It’s a marvel of miniaturization, with a conical bezel gear system that ensures consistent delivery of torque from the mainspring to the regulating system, regardless of the module’s orientation. It is made up of over 139 components, and if you are a watch aficionado, you want to see every single one of them!

Not everything about this timepiece is transparent. For example, a lapis lazuli dial sits above the fully exposed gimbal. But the three-piece sapphire case, offered in clear or blue-tinted, complements the star motif of the structural bridges themselves. Unfortunately, these heavenly watches are limited editions and may be just out of reach.

Bonus: G-SHOCK x thisneverthat

Sapphire-encased watches are justifiably rare. And expensive. But that doesn’t mean we all can’t wear something see-through on our wrist. Case in point: G-SHOCK recently teamed up with South Korean streetwear brand thisneverthat to create the DW5600TNT-7, a translucent take on its emblematic 5600 from the Eighties.

This workaday watch features all of the 5600’s hallmarks, including its 200m of water resistance, shock resistance, and five-year battery life. Plus, you also get the classic digital stopwatch, timer, alarms, and auto-calendar functions, as well as an LED backlight that illuminates the dial when needed.

All of this retro glory is housed in a frosted resin case with a matching strap. It’s clearly designed to make your friends jelly. (Get it? Jelly is see-through!)