FACT OF THE DAY

Beaubleu Paris Sets Out What a 5 ATM Marking Really Covers

The French independent's explainer treats the stamp on your dress watch as a lab result, not a depth gauge.

The French independent Beaubleu Paris has published a guide to the 5 ATM stamp found on countless dress watches and everyday three-handers.

The rating reflects a lab test under ISO 22810: a new watch, held still, subjected to the pressure of a 50 metre water column. Swimming strokes generate dynamic pressure the test never measures.

Rain, splashes, and handwashing are safe. Long swims, hot showers, saunas, and steam rooms are not. Diving calls for 20 ATM or more.

Gaskets age, so Beaubleu recommends a check every two to three years, or after a shock. In its words, “a crown poorly repositioned after adjusting the time is enough to nullify all water resistance.”

Source: Beaubleu Paris

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