In the press release, it doesn't specificially state the material of the ball bearings. It just says these ball bearings are not lubricated.
Hopefully Marcus knows the answer.
- AT

In the “Freak 28'800” (commercialized since April, 2005) the barrel turns in a ball bearing which assures both a better vertical and horizontal control and a considerable decrease in friction. This bearing is not lubricated.
Of course this is no exclusivity; ball bearings are widely used in winding rotors for instance. Ulysse Nardin has been using ball bearings in the Astrolabium since 1985. If the materials are carefully chosen in correspondence to the turnings speeds and pressures involved, there is no need for lubrication.