H. Moser & Cie. Unveils The Endeavour Perpetual Calendar Concept Tantalum
H. Moser & Cie. introduces the Endeavour Perpetual Calendar Concept Tantalum, a limited edition that blends mechanical complexity with a remarkably clean and restrained aesthetic.
At first glance, the watch presents itself with striking simplicity. Its uncluttered dial reveals very little, yet beneath it lies a fully integrated perpetual calendar—one of watchmaking’s most sophisticated complications—executed with a strong focus on usability and clarity.
A Perpetual Calendar Reimagined
Rather than relying on multiple sub-dials or apertures, Moser adopts a more intuitive display. The months are indicated by a central hand that discreetly points toward the hour markers, allowing the dial to remain open and highly legible. This solution avoids the visual congestion typically associated with perpetual calendars while preserving full functionality.

The mechanism itself has been engineered for everyday practicality. Unlike many traditional systems, the date can be adjusted forwards or backwards at any time without risking damage to the movement. This user-friendly approach is a defining feature of Moser’s perpetual calendar concept.
On the dial, only the essential indications are visible. Hours and minutes are displayed centrally, accompanied by a large date window. A subtle power reserve indicator is also present, though intentionally without a scale, while the central month hand integrates seamlessly into the overall design. The leap-year cycle, meanwhile, is positioned on the movement side, keeping the dial free from additional visual elements.
Tantalum Takes Center Stage
A key highlight of this release is the extensive use of tantalum, a rare and technically challenging metal employed for both the case and the dial.

Known for its exceptional resistance to corrosion and high density, tantalum also offers a distinctive aesthetic. Its naturally dark grey tone, combined with subtle blue undertones, creates a dynamic visual effect that shifts depending on lighting conditions. However, its extremely high melting point and hardness make it particularly difficult to machine and finish, adding a layer of complexity to its use in watchmaking.
For the dial, Moser has chosen a solid tantalum base with a finely brushed finish. It is left completely untreated, with no lacquer, fumé effect, or applied indexes. This allows the raw character of the material to take center stage, reinforcing the watch’s minimalist identity. In line with the “Concept” philosophy, the dial is also entirely free of logos or branding.
Manufacture Caliber HMC 800
Powering the watch is the in-house HMC 800 hand-wound movement, which reflects the brand’s commitment to technical refinement. The caliber measures 34 mm in diameter and maintains a relatively slim profile of 6.30 mm, despite its complexity. It is composed of 294 individual components and runs on 32 jewels, operating at a frequency of 18,000 vibrations per hour.

A notable feature of this movement is its impressive seven-day power reserve, delivered by a double barrel system. The inclusion of a gold escape wheel further highlights the level of craftsmanship involved, while the movement’s finishing can be appreciated through the sapphire caseback. The leap-year indicator is also positioned on this side, preserving the dial’s clean appearance.
Case and Wearability
The Endeavour Perpetual Calendar Concept Tantalum is housed in a 42 mm case with a thickness of 13.1mm, offering a balanced presence on the wrist. A curved sapphire crystal enhances the overall profile, contributing to the watch’s refined look.

Interestingly, while the main case is crafted from tantalum, the caseback frame is made of stainless steel. This is likely a practical consideration, given the challenges associated with machining tantalum components.
The watch is paired with a hand-stitched grey nubuck alligator strap, secured by a stainless steel folding clasp engraved with the brand’s signature.
Limited Production
This model is limited to just 50 pieces worldwide, reinforcing its exclusivity. With a retail price of CHF 75,000 before taxes, it sits firmly within the upper tier of high watchmaking.
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General Specifications:
Brand: H. Moser & Cie
Model: Endeavour Perpetual Calendar Concept Tantalum
References: 1800-2004
Dial: Tantalum
Case Material: Tantalum
Case Dimensions: 42 mm Diameter, 13.10 thickness
Crystal: Sapphire Glass
Case Back: Sapphire Glass
Water Resistance: 30 meters
Strap: Gray nubuck alligator leather strap with a stainless steel folding clasp
Calibre: HMC-800
Dimensions: 34 mm Diameter, 6.30 mm thickness
Functions: Hours, minutes, perpetual calendar (month, date, leap year), power reserve
Winding: Hand-wound
Frequency: 2.5 Hz (18,000 Vph)
Jewels: 32
Components: 294
Power Reserve: 168 Hours
Price: CHF 75,000 plus VAT
Limited Edition: Yes, 50 pieces
Availability: Now
















































