Steel on steel
Note: watch no longer available
Label given to a watch which has undergone precision tests and received a certificate from an official body (COSC).
The day of the month, displayed in a window on a watch dial typically at the 3 o'clock or 6 o'clock position.
Helium escape valve
Decompression system which allows helium to escape from inside the watch when the watch is worn for professional use in pressure chambers. (Long-term underwater work, crude oil exploration, etc.)
Self-locking crown, screwed into the tube of the case, used for highly water resistant divers' watches.
Get the latest edition of our official Omega catalogue "The Collection".