304 vs 316 Stainless Steel for Restraints

Every honest listing for a steel collar or cuff should name a grade, and most don't. "Stainless steel" alone is a range, not a specification — it stretches from cheap 201, which rusts against skin, up to surgical 316L. If a piece is going to close on a wrist or a throat for hours, the grade is the first thing worth knowing, and the one most sellers leave out. Here is what the numbers mean and which one we build in.

What the grades actually are

Stainless steel resists corrosion because chromium in the alloy forms an invisible oxide layer on the surface. The three grades you meet in this category differ mostly in what else is in the mix:

201 — the budget alloy. Less nickel, more manganese. It looks like stainless in the shop and spots with rust after real contact with sweat or body fluids. Anything unmarked and unusually cheap is almost always 201. Avoid it for anything worn against skin.
304 — the workhorse austenitic stainless, roughly 18% chromium and 8–10% nickel. Corrosion-resistant, non-magnetic, the same family used for cutlery, kitchen surfaces and quality watch cases. This is what a serious metal restraint should be, and what every piece we make is machined from.
316 / 316L — adds molybdenum for extra resistance to chlorides and salt. It is the marine and surgical grade; the "L" means low-carbon for welding. Genuinely better in seawater or an operating theatre, marginally better against skin, and noticeably more expensive.

The honest answer on 316

You will see fetish pieces marketed as "316L surgical steel" at a premium. For a collar or cuff worn indoors, the practical difference over well-finished, passivated 304 is small. What actually protects your skin is not the last percent of the alloy but the surface: a properly finished and passivated 304 piece presents a stable chromium-oxide layer, and that layer is what your skin touches. A rough or unpassivated 316 piece can behave worse than a well-made 304 one. Grade matters; finish matters as much.

We build in 304 and say so plainly, rather than charge a 316 premium for a difference you will not feel. Where a piece rests against the throat for the longest stretches — our Sovereign locking collar — the band is passivated for exactly this reason.

On nickel

The reassuring-sounding claim "low nickel" or "nickel-free" is usually wrong. Austenitic stainless steels contain nickel — around 8–10% in 304 — and it is part of what makes them corrosion-resistant and non-magnetic. What matters for skin is not how much nickel the alloy contains but how much it releases, and a passivated stainless surface releases very little. That is why surgical instruments and good watch cases come from the same family of alloys. If someone has a diagnosed severe nickel allergy, no austenitic stainless is truly safe against broken or long-occluded skin — that is a medical question, not a marketing one.

What to look for when you buy

A named grade — 304 at minimum. "Stainless" with no number is a warning.
A finish that is polished or brushed and passivated, not just tumbled.
Edges radiused and deburred where they meet skin.
A seller willing to tell you which is which. We list the grade on every product page.

The short version: buy 304 that is finished properly, not 201 dressed up, and don't pay a 316 premium for a room-temperature difference. Once the grade and the finish are right, the rest is fit — which is its own five-minute job.