Seikonaut Bracelet 20/16mm

It fits the Lucius Atelier case range — every Ultra Thin Edition case except the Bauhaus 33 (which has 18mm lugs), plus our classic-range cases (Datejust, Explorer, GS, GS Diver, and our SKX013 family). The end-links are shaped to seat against our case profiles. See the linked compatibility grid on the product page for the full list.

No. Unlike a strap or NATO — which fit any 20mm lug — our bracelets use solid end-links shaped to our case profiles. That precise fit is what makes them look built-in rather than bolted-on, but it means they won't fit OEM Seiko cases or generic 20mm lugs. They're made for Lucius Atelier cases only.

The links are joined by screw-type pins. Use a small precision screwdriver (not included) to back out the screws and remove links evenly from both sides of the clasp until it fits, then refit the screws. On clasps with micro-adjustment, set your base size by links first, then fine-tune at the clasp. Take care not to lose the tiny screws.

On a new bracelet, yes — the link screws ship slightly loose so you can resize easily. Before wearing, tighten every link screw fully with a small screwdriver. A tiny drop of threadlocker on each is optional but recommended — it stops them working loose over time. Once tightened, the bracelet is solid.

Yes — two spring bars come with every bracelet, ready to fit it to your case. No tools are included, so you'll need a spring-bar tool (or a small flat driver) to fit them.

All our bracelets are 20mm at the lugs. From there they taper to either 16mm or 18mm at the clasp, depending on the model — the 20/16 taper is slimmer and dressier, the 20/18 stays a touch more substantial. The taper is listed on every product page and in the collection comparison table.

Most are solid 316L stainless steel. The Settimo Yellow Gold adds a hard PVD gold coating; the DLC Oyster a Diamond-Like Carbon coating; and the Seikonaut Titanium is machined from Grade 4 titanium (with a 316L steel clasp and screws for thread durability). Each model's material is listed on its product page.

Three. A butterfly deployant opens from the centre and sits flush (our dress and sculpted bracelets). A Rolex-style clasp with five hidden micro-adjustments lets you fine-tune fit without removing links (the 20/18 Oysters). And our new toolless on-the-fly clasp lets you adjust on the wrist in seconds (the Oyster 20/16 Brushed).

Oyster — a rugged three-link sports bracelet. Jubilee — a supple five-link (since 1945). President — a refined three-piece (since 1956). Grand Seiko-style — clean, refined links. Settimo — a seven-link for maximum articulation and light. Seikonaut — a sculpted, original design. Pick by the look you want; the fit is the same across the range.

Mostly preference. A 20/16 taper narrows more toward the clasp for a slimmer, dressier line — it's our main lineup. A 20/18 keeps more width through to the clasp for a sportier, more substantial feel — currently on select Oysters. Both share the same 20mm lug fit; pick by the look you want on your build.

The bracelet itself is fine — solid stainless steel or titanium, both corrosion-resistant. Rinse with fresh water after swimming in salt water or chlorine, and dry it occasionally. Just note: a bracelet doesn't affect your watch's water resistance — that's determined by the case, crystal, and gaskets, not the bracelet.