• Métier horloger: l'empierrage de la Manufacture Jaeger-LeCoultre
In another unit the last complex and delicate operation on the plates and bridges - the jewelling, or setting of rubies - takes place. In use since 1902, these rubies have four functions: positioning the gear trains on the plates and the bridges; reducing friction; prolonging the piece’s lifetime; and serving as oil reservoirs for lubrication.