URWERK UR-105 Tantalum Hull

The URWERK UR-105 Tantalum Hull marks the end of the 105 Collection

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At URWERK we took radical decisions very early on: deciding to remain independent at all costs and limiting our growth despite all the advice to the contrary were among the most important. To continue staying true to ourselves, to remain URWERK, we make less than 150 pieces per year. This means that we reluctantly have to ‘kill’ a collection to bring a new creation to life. And time for the UR-105 CT is now running out,” explains URWERK co-founder Felix Baumgartner. The new Tantalum Hull is the last edition of the UR-105 CT and ends the 105 collections in style. Presenting the UR-105 TTH.

URWERK UR-105 Tantalum Hull

Tantalum is a very special metal. Its name comes from Tantalus, one of Greek mythology’s bad boys. Tantalum is precious, rare, and extremely painful to machine and finish. We made an UR-110 out of tantalum a few years ago – a first that almost was the last. The team made me promise never to use it again because tantalum ‘eats’ our CNC machines’ bits. It destroys them, reducing their life by a factor of three. But I love its blue-gray luster. Pure magic!” co-founder Martin Frei discloses.

URWERK UR-105 Tantalum Hull

Fortunately, as so often with URWERK, desire won over reason. The UR-105 TTH is a limited edition of just 12 pieces. “Tantalum is a precious metal weighing approximately the same as platinum. It has a solid presence on the wrist. To machine it is a nightmare, but it has incomparable beauty. Tantalum is one of the most URWERK-ian metals I know of. It is dark, almost anthracite colored, a shade which is an integral part of URWERK’s aesthetic signature,” confides Felix Baumgartner.

URWERK UR-105 Tantalum Hull

The UR-105 TTH – “TTH” stands for Tantalum Hull – is a beautiful object, substantial and pleasing to hold. Its distinctive octagonal form features deep streaks along its entire length. It is angular, geometric, and symmetrical with strong influence from the Art Deco style.

URWERK UR-105 Tantalum Hull

Martin Frei explains, “The UR-105 TTH comes with a protective cover, a breastplate that protects the mechanism. Tantalum is a perfect protective shield against corrosion. Hence its name Tantalum Hull.

URWERK UR-105 Tantalum Hull

Activating the sliding “tongue” of the UR-105 TTH opens the hull to reveal its mechanics, featuring a satellite time indication built on a new skeleton carousel. The latter supports four hour satellites, each displaying three hour numerals that rotate in turn along the minute track, providing both analog and digital time displays.

URWERK UR-105 Tantalum Hull

A power reserve indication and digital seconds complete the information on the dial. The digital seconds displaying the seconds in ten-second increments is particularly remarkable. To make it as light and as ephemeral as possible, the seconds disk was made using the LIGA photolithography process and the marker is openworked. The total weight of the display is less than 0.10 grams.

URWERK UR-105 Tantalum Hull

On the back, two turbines regulate the movement’s automatic winding system, which can be easily adjusted using a small lever according to how active the wearer is. In the “FULL” position, the slightest movement of the wrist is enough to wind the mainspring. In “STOP” mode, the automatic winding system is deactivated and the UR-105 is manually wound. A third intermediate position, “RED” (for REDUCED), moderates winding to minimize excessive tension and wear.

URWERK UR-105 Tantalum Hull


URWERK UR-105 Tantalum Hull Technical Specifications and Price

Limited edition 12 pieces


  • Calibre UR 5.03, automatic winding regulated by twin turbines
  • Jewels: 52
  • Frequency: 28,800vph / 4Hz
  • Power reserve: 48 hours
  • Materials:
    • Satellite hour Geneva crosses in beryllium bronze;
    • skeletonized carrousel in aluminium;
    • skeletonized nickel-phosphorus LIGA digital seconds;
    • carrousel and triple mainplate in ARCAP
  • Finishing:
    • Perlage, bead blasting, frosting
    • Screw heads with polished bevels
    • Hours and minute indexes hand-painted with Super-LumiNova
  • Indications
    • Satellite hours; minutes, digital seconds
    • Power reserve


  • Material: UR-105 CT “soap bar” case in titanium and tantalum
  • Dimensions: Width: 39.5 mm; length: 53mm; height: 17.8 mm
  • Crystal: Sapphire crystal
  • Water resistance: Pressure tested to 30 m / 3 ATM


  • Vulcarbon© rubber reference “Kiska” with black DLC buckle


  • CHF 77,000 (Swiss francs, excluding tax)

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