• Experiment ZR012

URWERK and MB&F have broken new horological ground by working together in an exciting new project called, C3H5N3O9, aka Nitro.

The movement was designed and developed by Felix Baumgartner, Martin Frei and URWERK constructor Cyrano Devanthey, while the case was designed and developed by Maximilian Büsser with designer Eric Giroud.
The fruit of this collaboration is Experiment ZR012, a limited edition of 12 pieces in zirconium and 12 pieces in black zirconium featuring a Wankel engine inspired display.

We became friends with Max Busser when we were working on Opus 5. Of course we shared a love of watchmaking, but we also had a common interest in cars as well as a taste for anything unconventional or unexpected. We wanted to come up with an idea that we could work on together. Our common admiration for the Wankel engine was the catalyst. We set about recreating it in the URWERK workshops. Max and his team took care of the case and the dream team was born.




Experiment ZR012 by C3H5N3O9 features Wankel engine inspired hour and minute indications in an asymmetrical zirconium case with articulated and compound lugs.

At first glance the time appears to be indicated by centrally rotating triangular rotors; however, the triangles are actually Reuleaux polygons; they rotate eccentrically rather than centrally and track complex epitrochoid curves rather than circles. The system was inspired by the Wankel engine, which features orbital Reuleaux polygon rotors rather than the reciprocating pistons that power the majority of our cars and machines today.

Technical details


Case in

Black zirconium and black titanium lugs


59mm long x 44mm wide x 17mm high (without lugs)


Sapphire crystal with anti-reflective treatment both side

Water resistance

Pressure tested to 3 ATM




C3H5N3O9, manual winding




28,800v/h, 4Hz

Power reserve

39 hours

Surface finishes

Satin finishing, sandblasted, circular graining on movement, black PVD treated components, black ruthenium treated components


Mechanical off-centered movement with satellite hour display and retrograde minute hand moving over a 120° counter; power reserve and day/night indication.
On the back: power reserve indicator