'Lumen' variatoin of the L951; at 454 it counts three extra parts over the L951.6. All 454 parts of the L951.7 manufacture calibre are lavishly finished. The sharply polished reentrant angle of many calibre components is an indication of the amount of work involved: this delicate, time-consuming process can only be executed by hand. The 8-gap column wheel coordinates all the switching operations of the chronograph mechanism. Rockers and levers of various shapes engage with this wheel. The considerable length of the levers is due to the special dial arrangement. They bypass the outsize-date mechanism and bridge the distance to the subsidiary dials located below the center line.