Based upon the utilitarian case design of a chronograph that was produced for the German Air Force in 1984, the Tutima M2 collection is the brand’s lineup of durable performance-oriented sports watches. Over the years, the M2 lineup has expanded to include a fairly diverse assortment of different models, and while some lean into a highly utilitarian and purpose-built design ethos, others take the core blueprint of the M2 series and turn it into something that can more easily exist in everyday life. Arguably some of the best examples of the latter variety of models are the 40mm versions of the Tutima M2 Seven Seas S that were released at the very end of 2022, which take the underlying design of the brand’s ultra-robust diver and render it in a more compact and refined overall package.

Within the greater Tutima M2 collection, the Seven Seas range is the brand’s lineup of dive watches that transform the M2’s modernized tonneau-shaped case into a function-forward diver with a 500-meter depth rating. While the original Seven Seas is crafted from titanium and offers a highly sporty and utilitarian design, the Seven Seas S is made from stainless steel, and it embraces a generally more refined overall aesthetic. While the original Tutima M2 Seven Seas S was launched with a 44mm case, a smaller 40mm version was later added to the collection, and its reduced size and revised proportions make it an excellent candidate for everyday wear and use, while still offering the same borderline-excessive water resistance that can quite literally accompany you to the bottom of the ocean.

Crafted from brushed and polished stainless steel, the case of the smaller version of Tutima M2 Seven Seas S offers an identical shape and profile to its larger siblings, although it has been reduced in just about every dimension possible. Measuring 40mm in diameter by 12.5mm thick, even the on-paper specs offer the impression that this particular version of the Seven Seas S will be quite manageable; however, Tutima M2 watches tend to wear even smaller than their official dimensions. Since Tutima’s M2 case doesn’t have any lugs in the traditional sense of the word, the “lug-to-lug” measurement for the 40mm Seven Seas S comes in at just 40.5mm, and even when you factor in the way that the end-links stick out past the edges of the case, you are still only looking at an approximate overall distance of 49mm. Additionally, despite being half a millimeter thinner than its full-size sibling, the smaller 40mm version of the Tutima M2 Seven Seas S is still able to offer the exact same 500-meter depth rating.

Just like the larger Tutima M2 Seven Seas S models, a signed screw-down winding crown sits between two large guards at the 3 o’clock location, while the solid screw-down stainless steel caseback features a large engraving of a ship. On the opposite side of the case, a 2.5mm thick flat sapphire crystal with anti-reflective treatment protects the dial, and just as you would expect from a dive watch, the crystal is surrounded by a unidirectional rotating timing bezel. The outer bezel ring features a mixture of scalloped edges with grooved sections, and fitted to this particular version (reference 6156-06) is a green ceramic insert with a 60-minute elapsed time scale in white. While the edge of the bezel isn’t the absolute easiest to grip, it does offer a smooth and solid 60-click action with virtually zero perceptible backplay whatsoever.

The dials fitted to the Tutima M2 Seven Seas S models all have a slightly more refined and dressy appearance compared to those from the standard titanium Seven Seas range, and a big part of this is due to their hour markers, which are applied tapered batons with polished facets and a rhodium-plated finish. On the version featured here (ref. 6156-06), the dial is a rich green color with a radial dégradé effect that darkens to black towards the outer edge. Just like the dials fitted to the larger version of the M2 Seven Seas S, the 40mm model also features a date window at the 6 o’clock location, and the green dial variant features all of its text in crisp white printing for added contrast. While the hour and minute hands receive a polished finish to compliment the indexes, the seconds hand is bright red for an additional dash of color, and all three of the hands, plus each one of the hour markers and the pip on the bezel are finished with Super-LumiNova that emits a green glow to help with visibility in low light settings.

Powering the 40mm Tutima M2 Seven Seas S is the same Tutima Caliber 330 automatic movement that can be found inside its larger siblings. At its core, the Tutima Cal. 330 is essentially the brand’s version of the popular ETA 2824 or SW200, and as such, it offers a proven design and the familiar specs of operating at a frequency of 28,800vph (4 Hz) with a power reserve of approximately 38 hours. Although the Tutima Cal. 330 is undeniably a bit inauspicious, it is also a very appropriate option for robust divers like those from the M2 range, and while it is easy to write this movement off for its ubiquitous design and comparatively short power reserve, it is ultimately a very practical option when it comes to daily use and long-term ownership. That said, due to the fact that variations of this same core movement can be found in watches at significantly lower price points, it would have been nice to see Tutima use a chronometer-certified equivalent, although this would have inevitably resulted in a higher retail price point, with only marginal real-world benefits.

Just like the larger version of the M2 Seven Seas S dive watch, Tutima offers the 40mm model with the option of either a stainless steel bracelet or a leather and rubber strap that is color-matched to the dial of the specific reference. Featuring a rounded H-Link design, the bracelet appears to have an integrated structure; however, the short end links actually mount into a fairly standard 23mm gap on the lower side of the case. With that in mind, since the end links attach to the case with pins rather than spring bars, the bracelet isn’t something that can be quickly swapped out (let alone removed without the use of any tools). Additionally, since the distance between the connecting pins and the case is minimal, some third-party straps may be too thick to comfortably fit, especially if they are of the single-piece or pass-through variety.

The end-links of the bracelet on the 40mm version of the Tutima M2 Seven Seas S flare out to 25mm in order to create an integrated appearance with the case, while the subsequent links offer a slight taper down to 21mm where they connect to the clasp. Although I would have personally preferred to have a bit more of a taper given the 40mm case size of the watch, the actual bracelet itself is quite solid and leaves little to be desired. Featuring a completely solid construction and single-sided screws for the removable links, the bracelet is completed by a machined folding clasp that features a double push-button release, four holes of micro-adjustment, and an additional fold-out wetsuit extension system. Additionally, while the vast majority of the bracelet is brushed, the sides of the links receive a high-polish finish to match the polished surfaces on the sides of the case.

While the 40mm version of the Tutima M2 Seven Seas S offers the same robust construction and impressive 500 meters of water resistance that defines the rest of the collection, its reduced case size and more refined styling make it ideally suited to be the overbuilt diver that you can comfortably wear in everyday life. The integrated appearance of its bracelet lends itself to a noticeably more elevated overall aesthetic, and despite the fact that the Seven Seas S is more than capable of standing up to serious diving use, it is also a model that would hardly look out of place when worn on dry land in more formal settings. With an official retail price of $1,980 USD on a strap or $2,350 USD when purchased on the bracelet, the 40mm version of the Tutima M2 Seven Seas S does initially seem slightly expensive for a diver powered by this known-quantity movement. However, what you are really paying for here is a very well-constructed case, along with a unique function-forward design that is emblematic of Tutima as a brand. For more on the Tutima M2 Seven Seas S 40mm collection, please visit the brand’s website.