Set of four watch keys in 18kt yellow gold. Models with enamel work, and one finished with lapis lazuli. Weight: 16 g. Measurements: 3 to 5 cm. This piece belongs to the personal collection of Don Juan José Ontalva (Chinchón, 1930- Madrid, 2019), a famous watchmaker from Madrid, descendant of several family generations dedicated to the world of watches. During his career he achieved a high degree of precision and skill, becoming the master of other watchmakers. He is currently recognised for numerous works, including the commissioning and restoration of the Billeter astronomical clock, located in the Congress of Deputies.