TAG Heuer Monaco V4 Next Generation Limited Edition in Rose Gold

Instead of usual gear trains, the Monaco V4 uses a set of transmission belts to transfer rotational energy from component to another. Although extremely thin, the belts are reinforced with real steel cords to increase their mileage.

To make the watch even more efficient, TAG Heuer substituted traditional synthetic rubies with tiny ball bearings, thus significantly reducing friction
— via World Watch Review