Editing Watch (section)

=== Scuba diving ===
{{Main|Diving watch}}
[[File:Seiko 7002-7020 Diver's 200 m on a 4-ring NATO style strap.JPG|thumb|upright|Seiko 7002–7020 Diver's 200&nbsp;m on a 4-ring NATO style strap]]

Watch construction may be water-resistant. These watches are sometimes called [[diving watches]] when they are suitable for [[scuba diving]] or [[saturation diving]]. The [[International Organization for Standardization]] (ISO) issued a standard for water-resistant watches which also prohibits the term "[[waterproof]]" to be used with watches, which many countries have adopted. In the United States, advertising a watch as waterproof has been illegal since 1968, per [[Federal Trade Commission]] regulations regarding the "misrepresentation of protective features".<ref>{{Cite web|last=The Timex Blog|title=WHAT MAKES A WATCH WATER-RESISTANT?|url=https://www.timex.com/the-timex-blog/what-makes-a-watch-water-resistant.html|url-status=live|access-date=27 December 2021|website=Timex|archive-date=27 December 2021|archive-url=https://web.archive.org/web/20211227183413/https://www.timex.com/the-timex-blog/what-makes-a-watch-water-resistant.html}}</ref><ref>{{Cite web|last=Federal Trade Commission|date=16 June 1997|title=FTC's Guides for Advertising and Marketing Watches Up for Review|url=https://www.ftc.gov/news-events/press-releases/1997/06/ftcs-guides-advertising-and-marketing-watches-review|url-status=live|access-date=27 December 2021|website=FTC.gov|archive-date=27 December 2021|archive-url=https://web.archive.org/web/20211227183419/https://www.ftc.gov/news-events/press-releases/1997/06/ftcs-guides-advertising-and-marketing-watches-review}}</ref><ref>{{Cite web|last=Code of Federal Regulations|date=1 January 1997|title=16 CFR 245.5 - Misrepresentation of protective features|url=https://www.govinfo.gov/content/pkg/CFR-1997-title16-vol1/pdf/CFR-1997-title16-vol1-sec245-5.pdf|url-status=live|access-date=27 December 2001|website=govinfo.gov|archive-date=27 December 2021|archive-url=https://web.archive.org/web/20211227183408/https://www.govinfo.gov/content/pkg/CFR-1997-title16-vol1/pdf/CFR-1997-title16-vol1-sec245-5.pdf}}</ref>

Water-resistance is achieved by the [[gasket]]s which forms a watertight seal, used in conjunction with a sealant applied on the case to help keep water out. The material of the case must also be tested in order to pass as water-resistant.<ref>{{cite web|url=http://www.europastar.com/europastar/watch_tech/waterresistance.jsp|title=Watch Industry Questions and Answers: Water-Resistance|work=Europa Star|publisher=VNU eMedia Inc|access-date=17 January 2007|archive-date=18 February 2007|archive-url=https://web.archive.org/web/20070218121615/http://www.europastar.com/europastar/watch_tech/waterresistance.jsp|url-status=dead}}</ref>

None of the tests defined by [[ISO 2281]] for the Water Resistant mark are suitable to qualify a watch for scuba diving. Such watches are designed for everyday life and must be water-resistant during exercises such as swimming. They can be worn in different temperature and pressure conditions but are under no circumstances designed for scuba diving.<ref>{{Cite web |date=2020-07-29 |title=What you need to know about water resistance |url=https://www.thewatchpages.com/is-your-watch-really-water-resistant/ |access-date=2023-11-14 |website=The Watch Pages |language=en-US}}</ref>

The standards for diving watches are regulated by the [[ISO 6425]] international standard. The watches are tested in static or still water under 125% of the rated (water) pressure, thus a watch with a 200-metre rating will be water-resistant if it is stationary and under 250 metres of static water. The testing of the water-resistance is fundamentally different from non-dive watches, because every watch has to be fully tested. Besides water resistance standards to a minimum of 100-metre depth rating, ISO 6425 also provides eight minimum requirements for mechanical diver's watches for scuba diving (quartz and digital watches have slightly differing readability requirements). For diver's watches for mixed-gas saturation diving two additional ISO 6425 requirements have to be met.

Watches are classified by their degree of water resistance, which roughly translates to the following (1 metre = 3.281 feet):<ref>{{cite web|url=http://www.jwnz.co.nz/page/watches.aspx|title=Watches|website=Jwnz.co.nz|access-date=28 October 2017|archive-date=15 July 2017|archive-url=https://web.archive.org/web/20170715033823/http://www.jwnz.co.nz/page/watches.aspx|url-status=live}}</ref>

{| class="wikitable"
|+ Main article [[ISO 6425#Water resistance classification|ISO 6425]]
|-
! nowrap="nowrap" |Water-resistance rating || Suitability || Remarks
|-
| Water Resistant or 30&nbsp;m || Suitable for everyday use. Splash/rain resistant. || <u>Not</u> suitable for diving, swimming, snorkeling, water-related work, or fishing.
|-
| Water Resistant 50&nbsp;m || Suitable for swimming, white-water rafting, non-snorkeling water related work, and fishing. || <u>Not</u> suitable for diving.
|-
| Water Resistant 100&nbsp;m || Suitable for recreational surfing, swimming, snorkeling, sailing, and water sports. || <u>Not</u> suitable for diving.
|-
| Water Resistant 200&nbsp;m || Suitable for professional marine activity and serious surface water sports. || Suitable for diving.
|-
| Diver's 100&nbsp;m || Minimum ISO standard for [[scuba diving]] at depths not requiring helium gas. || Diver's 100&nbsp;m and 150&nbsp;m watches are generally old(er) watches.
|-
| Diver's 200&nbsp;m or 300&nbsp;m || Suitable for scuba diving at depths not requiring helium gas. || Typical ratings for contemporary diver's watches.
|-
| Diver's 300<sup>+</sup>&nbsp;m helium&nbsp;safe|| Suitable for [[saturation diving]] (helium-enriched environment). || Watches designed for helium mixed-gas diving will have additional markings to indicate this.
|}

Some watches use [[Bar (unit)|bar]] instead of meters, which may then be multiplied by 10, and then subtract 10 to be approximately equal to the rating based on metres. Therefore, a 5 bar watch is equivalent to a 40-metre watch. Some watches are rated in [[Atmosphere (unit)|atmospheres]] (atm), which are roughly equivalent to bar.{{fact|date=August 2023}}