Explanatory notes
… means devices regulated by a balance‑wheel and hairspring, quartz crystal or any other system capable of determining … and hairspring combination, a tuning fork, a piezo‑electric quartz crystal or any other system capable of determining … , with a regulating device (tuning fork, piezo‑electric quartz crystal, etc.) which is kept oscillating by an …Legal note
… means devices regulated by a balance‑wheel and hairspring, quartz crystal or any other system capable of determining …