Seamaster Diver 300M 42 mm

Antimagnetic: The movement resists magnetic fields in excess of 1.5 tesla (15,000 gauss).
Master Chronometer certification: This certification guarantees the highest level of precision, performance and magnetic resistance in Swiss industry, as established by the Swiss Federal Institute of Metrology (METAS).
Chronometer: Designation of a watch that has passed precision tests and received a certificate from an official organization (the COSC).
Screw-in crown: self-locking crown screwed into the case tube, used for highly water-resistant diving watches.
Date: The day of the month, displayed in an aperture on the watch dial at 3 or 6 o’clock, or in a counter at 9 o’clock.
Transparent back: A transparent back, often sapphire, allows the movement inside the watch to be seen.
Unidirectional rotating bezel: Bezel turning in one direction only. Particularly useful for divers, as they can’t accidentally turn it in the wrong direction and thus miscalculate their dive times. A rotating bezel makes it easier to measure elapsed time.
Helium valve: Decompression system allowing helium to escape from the watch when worn by professional divers (long-term underwater work, offshore oil exploration, etc.).

Reference number: 210.30.42.20.04.001
Lug spacing: 20 mm
Height from horn to horn: 49.90 mm
Thickness: 13.56 mm
Case diameter: 42 mm
Case: Steel
Dial color: White
Glass: Domed, scratch-resistant sapphire crystal with anti-reflective coating on both sides
Water resistance: 30 bar (300 meters/1,000 feet)
Total product weight (approx.): 192 g
Caliber: Omega 8800
Movement type: Self-winding
Power reserve: 55 hours

Material: Steel
Clasp type: Folding clasp with ease of use and plunger extension