The complex chronograph/rattrapante mechanism is located on the movement side of the new L101.2 manually wound calibre. The control of elapsed or lap-time measurements is handled highly precisely in the classic manner with two column wheels. Like the rattrapante clamp that blocks the rattrapante hand in the lap-time display mode, it is visible through the sapphire-crystal caseback. This allows the precise switching processes to be observed in detail. When fully wound, the mainspring barrel delivers a power reserve of 58 hours. In connection with the screw balance, also manufactured in-house, the freely oscillating Lange balance spring guarantees excellent rate accuracy at a frequency of 21,600 semi-oscillations per hour (3 hertz).