Walter Lange, who passed away in January 2017, took the reins of the family firm in 1990. It was his lifelong wish to revive an invention by his great-grandfather Ferdinand Adolph Lange who, in 1867, conceived of a stoppable jumping seconds hand. This innovation became A. Lange & Söhne's first German patent, registered in 1877 as a "one-second movement with a jumping hand". This mechanism has at last been adapted to a wristwatch: the small seconds hand in the subsidiary dial at 6 o'clock makes six jumps per second, matching the frequency of the balance (21,600 vph). The sweep seconds hand, in contrast, makes one jump between seconds, thanks to a star combined with a tensioned lever arm or flirt. It can be stopped and restarted as required, to take someone's pulse for example, by a pusher at 2 o'clock. Also proposed in white gold or in pink gold, a "pièce unique" in steel was sold at auction for charity.