WR 200M / 20 Bar Marking — What This Mark Means
A water resistance rating of 200 meters (20 bar/ATM), suitable for serious water sports and recreational scuba diving. This is the standard entry-level rating for purpose-built dive watches.
What This Usually Means
A 200M rating indicates the watch was tested to 20 bar of static pressure and is suitable for swimming, snorkeling, surfing, and recreational scuba diving. Most watches with this rating are purpose-built dive watches with screw-down crowns and robust case construction. ISO 6425 certified divers undergo additional testing.
Where to Find It
On the case back as "WATER RESIST 200M," "WR200," "20 BAR," "W.R. 20ATM," "DIVER'S 200M," or "WATER RESISTANT 660FT."
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Common Variations
200M dive watches may also display "DIVER'S" or "DIVER'S 200M" if they meet ISO 6425 standards. Some show "20 BAR" or "20 ATM." Professional dive watches may carry even higher ratings like 300M or 1000M.
Common Misconceptions
Not all 200M watches are ISO-certified divers. The ISO 6425 standard requires additional testing beyond just pressure resistance, including magnetic resistance, shock resistance, and strap security. Also, the 200M rating has safety margins built in.
What to Do Next
If you plan to dive, verify your watch also carries ISO 6425 certification for added assurance. Maintain the gaskets regularly, avoid operating the crown underwater unless it's specifically designed for it, and always have the water resistance tested after any service that opens the case.
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Related Markings
A marking indicating the watch's tested water resistance depth, typically shown in meters, feet, bar, or ATM. This ratin
WR 100M / 10 Bar MarkingA water resistance rating of 100 meters (10 bar/ATM), generally considered suitable for swimming and recreational water
Bar / ATM Pressure RatingA water resistance rating expressed in bar or ATM (atmospheres) instead of meters. One bar/ATM approximately equals 10 m
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Frequently asked questions
Can I scuba dive with a 200M rated watch?
Yes, 200M is generally suitable for recreational scuba diving. For professional diving, look for ISO 6425 certification and higher depth ratings.
What's the difference between '200M' and 'Diver's 200M'?
"Diver's 200M" indicates ISO 6425 certification, which includes additional testing beyond pressure resistance such as shock, magnetic, and luminosity tests.
Do I need to screw down the crown before water exposure?
If your watch has a screw-down crown, always ensure it's fully screwed in before any water contact. An unscrewed crown compromises water resistance.
Is 200M enough for deep diving?
For recreational diving (typically up to 40 meters), 200M is more than adequate. Technical or saturation diving may require higher ratings.
How does a 200M watch achieve its rating?
Through a combination of screw-down crown, robust case construction, thick crystal, heavy-duty gaskets, and often a screw-down case back.
Can water resistance be restored after it degrades?
Often yes. A watchmaker can replace gaskets, reseal the case, and re-test to restore the original rating.