Seamaster Planet Ocean 600M

43.5?mm, steel on rubber strap

The movement is unaffected by exposure to strong magnetic fields, even those greater than 1.5 tesla (15,000 gauss).

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 at the 3 or 6 o??clock position, or within a subdial at 9 o’clock.

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.)

A series of watches whose production run is determined in advance of production and limited to a set number.

Self-locking crown, screwed into the tube of the case, used for highly water resistant divers’ watches.

Allows the hour hand to be easily adjusted to different time zones without stopping the watch.

A transparent caseback – frequently made of sapphire – makes it possible to see the movement inside the watch.

A bezel which turns in only one direction. Particularly useful for divers who cannot accidentally rotate it in the wrong direction, which could cause them to miscalculate their dive times. A rotating bezel makes it easy to measure elapsed time.