Who can dive below 2000m / 6560ft?

That is the most frequently asked question concerning the subject "water resistance".  But if you analyze the meaning of "water resistant to ... meters" and if you have a more detailed look into the requirements of the German watch standards DIN8310 (Water resistance of watches) and DIN8306 (Requirements and testing of diving watches) things are put in another perspective:

According to the DIN8310 (which correlates mostly to the International standard ISO2281) the test sequence for watches carrying the marking "Water resistant" in combination with a declaration of the pressure (which is often replaced by a declaration in "meters") is as follows: 

Step1: Check of pressure tightness when putting the watch in a depth of 10 cm
- Exposure time t=1h
- Afterwards condensation test

Step 2: Check of pressure tightness when using the operating elements 
- Watch is fully exposed into water
- Test force of  5N on the crown (across to the winding stem) and pushers
- Test time t=6 min
- Afterwards condensation test

Step 3: Check of pressure tightness with water over pressure Δp
- Watch is fully exposed into water inside a pressure vessel
- Over pressure Δp is built up within t=1 min
- Over pressure Δp is sustained for t=5 min
- Afterwards condensation test

In addition to that, a watch that carries the marking "Diving watch - 200m" according to the DIN8306 needs to pass the following test sequence: 

a) Exposure in a water depth L (in this example 200m) over a period of time of 2 hours. This water depth equals an outer over pressure of Δp = 0,1 x L = 0,1 x 200m = 20 bar.

b) Exposure in a water depth of 3 m over a period of time of 3 hours, Δp = 0,3 bar.

According to the described test sequences there 2 conclusions:
1) The test pressure has only a static character.
2) Water resistance is a value tested for a limited period of time.

Quotation from the DIN8306 (translated from German):
"A diving watch is a watch dedicated for diving within a limited period of time."

Watches with a water resistance declaration in meters cannot be used directly in this depth (e.g. when scuba-diving), as the declared depth in meters should only be understood as an illustration of the static test pressure (e.g. 20bar equal the pressure of  200m water column). By movements inside the water, e.g. rapid swimming or a hit on the water surface the resulting dynamic pressure can far exceed the static one and affect  the declared water resistance. In addition to that, you should consider, that the average time of a dive exceeds the test time of  the DIN8310, too. This explains the current recommendations of the watch industry towards the usage of watches in combination with water: 

Therefore it makes sense during professional diving to use a diving watch that has passed the described test sequences with a much higher test pressure (e.g. 200 bar = 2000m water column), as it will -  in direct comparison with a watch that ist tested e.g. only with 10 bar = 100m - withstand dynamic pressure peaks and a longer residence time under water much better.

Remark: The SONIC BARRACUDA 2000M was - according to the requirements of the DIN8310 and DIN8306 - successfully tested with a pressure of 200bar. Therefore it justifiably carries the declaration "Diving Watch 2000M - DIN8306".

Please take note, that water resistance is no everlasting property, as the installed sealings are subject to natural deterioration and wear. Extremely high and low temperatures, solvents and cosmetics accelerate this process, that makes sealings get brittle and porous. As a result  the water resistance is not ensured any longer. 

Therefore, we recommend a water resistance check once a year at our service department.