Purchasing a diving watch? – 5 important things to look for.

A diving watch is very different from a water-resistant watch. A water-resistant watch is merely made of water-resistant materials and sealed against the entry of water, usually with a rubber gasket, to withstand leakage while swimming or bathing. But conditions at the bottom of your pool are very different from conditions deep underwater, where the ambient pressure is very high, so a diving watch must be designed to certain specifications.

Here are some  important things to look for in a good diving watch:

1. Readability of the face. The deeper you dive, the darker it gets– your diving watch is useless without a lighting element. Also, the markings on the face should be large enough for you to read easily at a comfortable distance.

2. Stability of the strap. Make sure the strap attaches securely to your wrist and to the watch face.

3. Water resistant mark. This is usually printed on the face of the watch or etched on the back plate; on watches designed for everyday use it might say, “WR 10m.” This does not mean that the watch is water resistant at a depth of 10 meters underwater, but that the watch is reliably water-resistance under enough pressure to lift water 10 meters– atmospheric pressure at sea level. So, a watch marked “WR 10m” is designed to resist splashes of water on the beach. A watch marked “WR 50m” is designed to resist water at the bottom of a swimming pool. A diving watch needs a water-resistant mark of at least 200m.

4. The ATM rating. ATM, or atmosphere, is the standard unit to measure atmospheric pressure. A watch with an ATM rating of 1 is equivalent to a watch with a water-resistant mark of 10m; therefore, a diving watch should have an an ATM of at least 20.

5. ISO 6425. A watch built to ISO 6425 standards will probably be a safe bet, because it has been tested for all of the above qualities and more, including magnetic resistance, shatter resistance, rust resistance, and a long battery life.