Yema Superman Slim CMM.20 Review: Exploring Its Slimmer Dive-Watch Design

The Superman has long been recognized for its distinctive dive-watch character, combining practical functionality with a design that has remained closely tied to Yema’s identity. Over the years, the collection has evolved through different interpretations, adapting its signature elements to meet changing preferences while retaining its recognizable character.

One of the more refined interpretations is the Yema Superman Slim, which takes the familiar Superman design and gives it a slimmer, more versatile profile. Developed around Yema’s Manufacture CMM.20 micro-rotor caliber, the model pairs its dive-watch heritage with a thinner 39mm case and a more elegant presence on the wrist.

This approach also reflects Yema’s heritage as an independent French watch manufacturer, with the brand continuing to develop and assemble its timepieces in Morteau, the historic heart of French watchmaking. From its tool-watch origins to its modern Manufacture movements, Yema continues to connect its contemporary models with its longstanding horological identity.

So, what makes the Superman Slim different from other models in the collection? Let’s explore its design, movement, and key features in this article.

The Sleeker Side of the Superman Collection: Yema Superman Slim

Within Yema’s iconic Superman collection, the Superman Slim takes a more streamlined approach to the brand’s signature dive-watch design. Rather than moving away from the characteristics that define the Superman, this model refines them through a thinner case and more elegant proportions. Measuring 39mm across, the Superman Slim is designed to offer a more versatile presence on the wrist, making it suitable for both everyday wear and more formal settings.

The slimmer construction is made possible in large part by the Manufacture Morteau 20 (CMM.20), Yema’s in-house micro-rotor caliber. Its compact architecture allows the watch to maintain a relatively thin profile while retaining the mechanical character expected from the Superman line. This gives the Superman Slim a distinct position within the collection, combining the practical identity of a dive watch with a more refined and understated wearing experience.

The model also reflects Yema’s broader identity as an independent French watchmaker. Founded in 1948 by Henry-Louis Belmont, the brand built its reputation around functional watches designed for demanding activities, including diving, aviation, sailing, and military use. The Superman itself became an important part of that history in 1967, when Yema introduced its patented bezel-lock mechanism to prevent accidental bezel movement during a dive.

That tool-watch heritage continued to shape the Superman over the decades, including its association with the French Air Force’s Search and Rescue swimmers in the 1970s. The modern Superman Slim carries that historical design language into a more contemporary format, preserving the collection’s recognizable character while reducing the visual and physical bulk of the watch.

The result is a Superman that feels less utilitarian in its proportions without losing its underlying purpose. With its 39mm case, slim profile, and in-house micro-rotor movement, the Yema Superman Slim offers a more polished interpretation of the collection, one that can transition from outdoor activities to formal occasions with greater ease.

Read also: Steinhart Ocean One: Explore the Depths of Dive Watch Design

The Yema Superman Slim CMM.20: A Slimmer Take on the Iconic Superman

The Yema Superman Slim CMM.20 is a model within the brand’s renowned Superman collection, bringing the signature dive-watch design into a more streamlined form. While it retains the visual cues that have long defined the Superman family, this version places greater emphasis on a slimmer profile and refined proportions.

The model is available with either a black or blue dial. For this review, the focus is on the black-dial version, which gives the watch a more understated and versatile appearance while complementing its stainless steel construction.

1. Powered by Yema’s In-House Micro-Rotor Engineering

At the heart of the Superman Slim CMM.20 sits the Manufacture Morteau 20, Yema’s in-house micro-rotor movement developed to deliver both a compact profile and strong mechanical performance. Its architecture plays a central role in allowing the watch to achieve its notably slim dimensions without giving up the functionality expected from a serious dive watch.

The movement uses a tungsten micro-rotor mounted on ball bearings to generate energy as the watch is worn. Unlike a conventional full-size rotor, the micro-rotor is integrated within the movement rather than occupying a separate layer above it. This construction helps reduce the overall thickness of the caliber and, in turn, contributes to the watch’s streamlined case.

The CMM.20 operates at a frequency of 28,800 vibrations per hour, or 4 Hz. This relatively high beat rate supports smooth movement of the seconds hand while contributing to the caliber’s timekeeping performance. The movement also provides a power reserve of approximately 70 hours, allowing the watch to continue running for nearly three days when fully wound.

Yema developed the CMM.20 with an emphasis on durability as well as compactness. Its movement architecture incorporates a redesigned hand-setting system intended to improve resistance against shocks and vibrations. The result is a caliber designed not merely to make the watch thinner, but to maintain the mechanical robustness associated with the Superman name.

The Manufacture Morteau 20 therefore represents a significant part of the Superman Slim CMM.20’s identity. By combining an in-house micro-rotor construction with a slim mechanical architecture, Yema manages to bring together a more refined wearing profile and the technical character expected from a modern mechanical dive watch.

2. A Black Enamel Dial with Purpose-Built Dive Legibility

The black version of the Superman Slim CMM.20 features a lacquered enamel dial that gives the watch a rich, clean appearance. Its dark surface creates a strong backdrop for the polished hands and printed hour markers, allowing the essential indications to remain easy to distinguish at a glance.

The dial is intentionally free from a date window, creating a more symmetrical layout across its surface. Removing the date display also gives the dial a cleaner visual balance, which works particularly well with the watch’s restrained proportions. This simplicity reinforces the model’s focus on legibility and function.

For visibility in darker environments, the watch uses Super-LumiNova C1 Grade A. The luminous material is applied to the hands and hour markers, helping the indications remain readable when ambient light becomes limited. The bezel also incorporates a luminous marker, extending the watch’s low-light functionality beyond the dial itself.

The watch is protected by a 2.00 mm double-domed sapphire crystal. Its curved profile contributes to the vintage-inspired character of the Superman Slim while providing strong resistance to scratches. The elevated crystal also adds visual depth to the dial without making the overall watch excessively bulky.

Together, the black lacquered enamel dial, luminous details, date-free layout, and double-domed sapphire crystal create a display that balances retro character with modern practicality. Rather than adding unnecessary elements, YEMA keeps the dial focused on the information that matters most for everyday and underwater use.

Read also: 8 Top Squale Dive Watch Recommended for Your Next Dive

3. A 39mm Dive Watch with a Slimmer Superman Profile

The Superman Slim CMM.20 retains the recognizable case architecture associated with YEMA’s dive-watch lineage while adopting more compact proportions. Its 39mm diameter makes the watch relatively restrained on the wrist, while the 48mm lug-to-lug measurement gives it a balanced footprint. Most notably, the case measures just 9.95mm thick, a dimension that sets this model apart from many mechanical dive watches.

The case is crafted from 316L stainless steel and combines vertical brushing with polished bevels. This finishing creates a subtle contrast across the case surfaces, adding definition without distracting from the watch’s utilitarian character. The pointed lugs further reinforce the Superman’s established silhouette.

At 3 o’clock, the screw-down crown carries an embossed Yema logo and contributes to the watch’s secure construction. The crown architecture has also been refined for smoother operation when winding and setting the movement. Combined with the Superman’s distinctive crown-locking system, it preserves an important element of the collection’s identity.

The unidirectional diving bezel features a sapphire insert with a 0-to-60-minute graduation. This allows the wearer to align the bezel with the minute hand before a dive and monitor elapsed time underwater. Its unidirectional construction also provides a safety-oriented design, as accidental movement can only indicate less remaining dive time.

With 300 meters of water resistance, the Superman Slim CMM.20 offers substantial capability for underwater use. The combination of a 39mm case, sub-10mm thickness, secure crown construction, and functional dive bezel demonstrates how Yema has prioritized a slimmer wearing experience without stripping away the core specifications of the Superman platform.

4. A Brushed Steel Bracelet Built for Diving

The Superman Slim CMM.20 comes fitted with a 316L stainless steel bracelet finished entirely with brushing. Its surface treatment complements the vertically brushed case and gives the watch a cohesive appearance from the case to the wrist. The bracelet also contributes to the model’s distinctly tool-watch character.

The bracelet uses a double-security folding clasp to keep the watch firmly secured on the wrist. This construction provides an additional layer of security during active wear, which is particularly useful for a watch designed with diving in mind.

A diving extension is integrated into the bracelet, allowing the wearer to expand its length when the watch needs to be worn over a wetsuit. This feature makes the bracelet more practical for actual underwater use rather than limiting it to everyday wear.

The 20mm lug width provides the connection between the case and bracelet while maintaining the watch’s relatively compact proportions. Combined with the brushed 316L steel construction, the bracelet feels purpose-built for the Superman Slim’s slimmer case rather than simply serving as a decorative finishing touch.

Overall, the steel bracelet reinforces the Superman Slim CMM.20’s balance between vintage-inspired design and modern dive-watch functionality. Its secure clasp, brushed finish, and diving extension make it a practical match for the watch’s 300-meter water resistance and professional-oriented specifications.

Final Thought

The Yema Superman Slim CMM.20 offers a fresh interpretation of the brand’s iconic dive-watch formula without losing the character that makes the Superman recognizable. Its 39mm case and 9.95mm thickness give it a noticeably more streamlined profile, while the 300-meter water resistance, unidirectional bezel, and screw-down crown preserve its practical dive-watch credentials.

The in-house CMM.20 micro-rotor caliber further sets this model apart. Its compact construction contributes directly to the watch’s slim proportions, while the 4Hz frequency and approximately 70-hour power reserve provide the mechanical performance expected from a modern automatic timepiece. Paired with the black lacquered enamel dial, Super-LumiNova C1 Grade A, and double-domed sapphire crystal, the overall package balances technical functionality with refined aesthetics.

For enthusiasts considering a Yema Flygraf review, the Superman Slim CMM.20 offers a different perspective on what YEMA can deliver beyond its aviation-inspired watches. Instead, this model focuses on the brand’s long-standing dive-watch heritage and demonstrates how that identity can be adapted into a slimmer and more versatile format.

Ultimately, the Superman Slim CMM.20 stands out as a compelling choice for those who appreciate the distinctive Superman design but prefer a watch with more restrained proportions. Its combination of French watchmaking heritage, an in-house micro-rotor movement, capable diving specifications, and polished finishing makes it an interesting addition to YEMA’s modern collection.

Read also: Yema Superman Steel CMM.10 Review: Features, Design, and Performance