On a product page, "stainless steel" doesn't mean much. There are dozens of grades, and the quality gap between them is considerable. The number that follows is the only information that matters.
What 316L refers to
316L is an austenitic stainless steel, also known as surgical steel — it's what medical instruments and implants are made of. Its composition contains chromium, nickel, and most importantly, molybdenum, which is absent in more common grades.
The "L" stands for low carbon: low carbon content. Specifically, the steel is more resistant to corrosion in welded or machined areas — exactly where a watch case is most stressed.
The difference with 304
304 is the most common stainless steel: sinks, cutlery, household appliances. It's perfectly adequate for these uses. But it does not contain molybdenum.
Molybdenum is what protects against pitting corrosion, caused by chlorides — that is, perspiration, seawater, cleaning products. On an object worn against the skin twelve hours a day, the difference eventually shows: small dark spots that first appear in the crevices.
What about plating?
A "gold-plated" watch has a case made of any metal covered with a layer of a few microns. This layer wears off, and it wears off where it rubs: the edges, the back, the buckle. After one or two years, the gray metal appears in patches.
This is irreversible. Solid steel, however, scratches but remains the same steel from surface to core. A micro-scratch on 316L exposes nothing but 316L.
Nickel, and sensitive skin
316L contains nickel, but it is chemically bound in the alloy: it hardly migrates on contact with the skin. This is precisely why it is used in surgery and piercing jewelry.
Skin reactions to a watch most often come from other sources: an improperly dried strap, soap residue trapped in a link, or a strap that is too tight and prevents the skin from breathing. Our article on maintenance details the right steps.
Why we only use this one
All our cases are made of 316L stainless steel, including the engraved back. And including our gold or rose gold plated models: the back always remains gray 316L, untreated. This is the side in permanent contact with the skin, the one that must resist the longest.
Our Milanese mesh straps are made of the same steel. A strap of an inferior grade on a 316L case would be nonsensical: it's the strap that absorbs perspiration.
How to check it on any watch
Look for the exact mention, not just the word. "Stainless steel" without a specified grade usually means 304, or less. A brand that uses 316L will state it, because it costs them more.
Also beware of "alloy," "metal," or "steel finish": these formulations refer to anything but solid stainless steel.
The composition is listed in the Details tab of each of our product pages, under "Material." You can check it on the Azurite, the Muguet, or any other model from our women's and men's collections.
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