FEATURED: URWERK UR105 Tantalum Hull - Marking the end of the 105's

THM Desk
26 May 2021 |
clock icon5 min read
like image
comment icon image
like image
SUMMARIZEarrow down

Irreverent, rebellious, eccentric can each describe URWERK’s watchmaking with varying accuracy, but it's watches unerringly open the way forward for mechanical watchmaking in the 21st century. Although URWERK is a young company established in 1997, it is certainly recognised as a pioneer among independent watchmakers.


Co-founders of URWERK, Felix Baumgartner and Martin Frei developed their first watch in the early nineties, inspired by the 17th-century night clock built by the Campanus brothers. In it, each hour on a rotating disc rises and sets in an arc like the sun. The wandering hour has since formed the basis for URWERK’s astonishing 103 and 201families. Both feature highly original design, advanced watchmaking techniques and new concepts such as the control board.

It was in 2014 that we witnessed the introduction of the UR105, with the manual-wound UR105M followers by the automatic UR 105TA. Since then, with the UR105 as the base, this collection has seen various forms with different finishes and materials such as bronze, gold and bold extravagant colours like the clockwork orange, which I thought was quite cool.

Just as all things must come to an end, this year URWERK marks the end of the UR 105 with it’s last edition : the URWERK-105 CT Tantalum Hull.


“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.

So why end the collection with a metal that is extremely painful to machine and finish? Well, Tantalum is a precious metal weighing approximately the same as platinum and although it is a nightmare to machine, it surely has a solid presence on the wrist. 

URWERK UR105 Tantalum Hull

“Tantalum is a very special metal. Its name comes from Tantalus, one of Greek mythology’s bad boys. We made a 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.

“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.” concludes Felix Baumgartner.

URWERK UR105 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." 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.

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 UR105 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.

Once again, as so often with URWERK, desire won over reason with one of the most URWERK-ian metals used in a watch and the result is a lustrous blue-grey magical wrist machine. The UR-105 TTH is a limited edition of just 12 pieces.

Approximate Price: CHF 77,000 (excluding tax)

*Did you know: The name URWERK comes from the ancient city of Ur of the Chaldees in Mesopotamia, founded nearly 6,000 years ago where the Sumerian inhabitants first established units of time based on the shadows cast by its monuments. Ur in the German language also means primeval or original and Werk means an achievement or a mechanism. Thus, URWERK can be translated as an original movement — a tribute to generations of watchmakers whose work has resulted in what we know today as haute horlogerie, or superlative watchmaking