Tusenö has been around for less than a decade and, in many ways, is following a path already well-trodden by microbrands around the globe. The brand’s first watch, a meca-quartz chronograph, was successfully crowdfunded in 2015. That was followed by its first automatic dive watch, produced in collaboration with the SSTS (Swedish Sea Rescue Society). Fast forward to 2021, and Tusenö launched the Shellback in limited numbers. This Swiss-made, automatic dive watch is designed to cope equally well beneath the waves or behind a desk.

As someone who is quite adept at desk diving and not much beyond, my judgment of the capabilities of a true tool watch is usually limited to ticking boxes. After that, any watch’s credentials as a dressier piece come down to aesthetic design choices. I feel a little more at home in saying that Tusenö nailed it on that front. So, how does the Shellback stack up in an already heavily saturated arena?

Black and blue

Tusenö offers the Shellback in two dial colors, each with or without a date display. The brand sent in a dateless version with a glossy black dial and one with a brushed blue dial with a date to look over. Despite the many shared features, the change in dial texture alone is enough to deliver two somewhat contrasting watches. Of the two, the glossy black dial is perhaps less interesting, but this also makes it the more versatile choice. The glimmer from the dial is matched by the ceramic bezel insert and enhanced further by the polished framing of the hands and indices.

The vertically brushed blue dial is altogether more dynamic. At times shadowy and masking its color, the dial can show off texture and saturation in a different light. The use of ceramic for the bezel insert here helps to give a shock of brilliant blue no matter what character the dial is giving off. Whereas the black dial is a one-trick pony, I find that the blue has much more to offer.

Tusenö Shellback

The Tusenö Shellback is a diver that stands out in a crowded pool

Despite introducing the Tusenö Shellback as another dress-diver, the design has a few quirks that I feel help it stand out. The use of a sandwich dial adds a sense of depth to the watch, but what is unusual is the polished frames around the sandwich hour indices. Where the date window is present, this is positioned at 6 o’clock and framed in the same fashion with a sliver of the lumed sandwich dial also making an appearance. All three hands as well as the minute track feature the same BGW9 lume to some degree.

Tusenö Shellback

A modern take on the Mercedes hand?

Perhaps my favorite detail of the Shellback is the hour hand. The punched hole feels like a more modern take on a Mercedes hand, but I especially like how the framing of that hole plays against the framed cutouts on the dial. The placing of the “Shellback” text in the lower half of the dial also corresponds to the hour hand as it sweeps by. However, that window will only reveal a couple of letters at a time, and it will take nearly two hours to see it spell out the model name (in reverse order).

By contrast, the case is relatively simple. The straight and pointed lugs offer a more serious backdrop to the lively dial, bezel, and handset. The majority of the case is brushed stainless steel with a polished facet that runs from the top lug to the bottom. Viewed in profile, the Shellback exhibits good proportions. The mid-case is slim with a usable amount of the coin-edge bezel sitting above. With additional height coming from the angled bezel and slightly domed sapphire crystal, the watch comes in at almost 13mm thick, but due to the curvature that starts from the lugs, it feels slightly thinner.

A Swiss engine

Inside the Shellback is the Ronda R150, a Swiss automatic movement. I don’t have any prior experience with this movement to fall back on, but in terms of specifications, it competes directly with similar offerings from ETA and Sellita. The R150 hacks, hand-winds, beats at 28,800vph, and has a power reserve of 40 hours. Expected accuracy is ±12 seconds per day, and although Tusenö does not advertise any regulating beyond this, I’ve been happy to see much tighter performance over a week.

Tusenö Shellback

A well-proportioned design for most wrists

The Shellback measures just under 40mm in diameter with a lug-to-lug length of 47mm. At this size, it is ideal for my 7″ wrist, and it should fit many others just as well. The three-link bracelet’s finishing mirrors that of the case with vertical brushing and polished chamfers running down the sides. While the clasp is sizeable, both in thickness and length, it does offer the ability to extend on the fly. The black-dial variant looks perfectly at home on the bracelet. By contrast, I find the blue dial needs something a little less reserved.

Tusenö Shellback

A plethora of strap options for versatility

Tusenö offers Tropic-style rubber straps and nylon military straps in black and blue to match these watches. Tusenö fitted the Shellback bracelet with quick-release spring bars, which makes switching it out for something else nice and easy. I’ve enjoyed the blue Shellback on a matching nylon strap. However, that lifts the case further from the wrist due to the strap’s added bulk. One drawback of creating a slim mid-case is the necessity to have a slightly bulbous case back beneath it.

Tusenö Shellback

The Tusenö Shellback is a turtle perhaps more at home on land

The Shellback name derives from the toughness of a turtle shell. This was also the name given to the hardiest of Swedish seafarers. Although I’m sure that the Shellback, with its 200m water-resistance rating, is a capable dive watch, I can’t help but feel that it belongs more at home on the wrist of desk divers like me. The Shellback retails for SEK 7,995 / €799.50 / US$649, and you can find more details on the official Tusenö website.

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