Set of 17 keys; 18th-20th century. Iron and bronze. Some of them have been restored. Measurements: 10,5 cm (largest). Set of seventeen keys belonging 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.