RS1719 Shogurai Rubber Strap — FKM on solid steel end links, for the Seiko SRPL11, SRPL13 and SRPL15

The RS1719, in black FKM rubber on brushed steel end links.

Put a rubber strap on most divers and you accept a small compromise at the lugs. The strap sits between them, a gap opens either side of it, and a watch designed as one piece suddenly looks like it’s wearing something borrowed. The RS1719 doesn’t ask for that trade. It’s an FKM rubber strap that meets the case on solid stainless steel end links shaped for the Shogurai — the clean transition you get from a bracelet, on rubber.

Seiko’s redesigned Samurai — the one the community named the Shogurai — came in three references, and the RS1719 is cut for all three. If you own the SRPL15, this is the sports strap for a watch that didn’t arrive on a bracelet at all. If you own the SRPL11 or SRPL13, it’s what you wear when the steel is more watch than the day needs.

Does It Fit? The Short Version

Yes, if you own one of these:

• SRPL11 — the burgundy
• SRPL13 — the black dial on steel
• SRPL15 — the black-coated

All three take it on the same 20mm female end link, and the strap narrows to 16mm by the time it reaches the clasp.

If yours is on that list, the strap is here: RS1719 FKM Rubber Strap with End Links.

And the part worth reading twice, because it runs the opposite way to most rubber straps: this one is cut for the Shogurai case specifically. Other Seikos with 20mm lugs may not take it — the end link is shaped for this case, and case and end-link dimensions differ from model to model.

Why the End Links Are the Point

The steel end link closes the gap at the lugs, so the strap starts where the case stops.

An ordinary rubber strap is a universal part. It’s cut to a width, it sits between your lugs, and it fits anything of that width — which is convenient right up to the moment you look at the watch side-on and see daylight where the case should be meeting the strap.

An end link is the piece that closes that gap. It’s the curved section that follows the case profile down and hands off to the strap, and it’s normally the preserve of steel bracelets — it’s the reason a good bracelet reads as part of the watch rather than something bolted to it. Fitted end links on a rubber strap are the unusual part here, and they’re most of what you’re paying for.

That cuts both ways, and it’s the same lesson as the bracelet side of this watch: width on its own never settles whether something fits. We wrote that out in full in the Hexad bracelet guide, and the RS1719 sits on exactly the same principle — as case-specific as a fitted steel bracelet, for exactly the same reason.

What You’re Getting

Brushed steel at the lugs, black rubber through the rest.

On an SRPL11 or SRPL13 the brushed end links pick up the finish of the case, so the join reads as one piece of hardware rather than two. On the black-coated SRPL15 they do the opposite and give you a deliberate flash of steel at the lugs — a two-tone that looks chosen rather than accidental.

Why FKM Rather Than Ordinary Rubber

Two things separate FKM — fluororubber — from the conventional rubber most straps are cut from.

The first is how it wears. It’s soft and flexible without going slack, resistant to heat and chemicals, and strong enough to be the strap you leave on the watch rather than the one you keep for weekends.

The second is the one nobody expects until they’ve lived with a rubber strap: FKM doesn’t carry the rubber odour. That faint chemical note a conventional rubber strap gives off is the reason a lot of people quietly go back to steel. This is the version that doesn’t do it.

The 16mm Clasp End

16mm at this end — where the folding clasp that comes with it attaches.

The RS1719 finishes at 16mm, down from 20mm at the lugs — the same taper the Hexad bracelet uses, and what keeps the proportions from going top-heavy. The strap comes with its folding clasp — the one in the photograph above — so there is nothing else to buy before you can wear it.

If you would rather change it, two of ours fit the 16mm end.

Our pick if you do: B1420 Sub Divers Clasp - Brushed Finish in 16mm — 40mm long, 8mm thick, 316L stainless, with six micro-adjustment holes. The brushed finish sits naturally against the brushed steel end links this strap already has. Alternative:

• B0797 V - Clasp in 16mm — the same 316L and the same six points of micro-adjustment, with a V-shape safety lock on top

Rubber or Steel?

The Shogurai now has two ways off its factory strap or bracelet, and they aren’t really competing — they cover different days.

RS1719 FKM Rubber Strap. Lighter on the wrist, quieter, and the more comfortable alternative to the bracelet the SRPL11 and SRPL13 arrive on. It keeps the integrated look, and it rinses clean under a tap.

SB1703 and SB1704 Hexad Bracelets. Full 316L steel, solid screw links, in brushed silver or brushed black. That’s the one that dresses the watch up rather than down — the full guide is here.

Both meet the case on the same 20mm female end link and both taper to 16mm, so whichever you start with, the other is a straight swap later.

Fitting It

The lugs on these cases are drilled, so the strap goes on and off from outside the case. A pin pushed through the small hole in the side of each lug releases the spring bar directly, which keeps every tool tip away from the flank of the case and out of the gap between the lugs.

Fitted end links go on the way a bracelet’s do: line the end link up against the case, drop the spring bar into the lug holes, and it seats itself. If you’ve changed a bracelet before, this is the same job. If you haven’t, it’s the easiest version of it.

Shop it: RS1719 FKM Rubber Strap with End Links · all Shogurai straps and bracelets

FAQ

Which watches does the RS1719 fit?
Seiko SRPL11, SRPL13 and SRPL15 — the three Shogurai references.

Will it fit another Seiko with 20mm lugs?
Not necessarily. It’s designed for the SRPL Shogurai case, and other models with a 20mm lug width may not be compatible, because case and end-link dimensions differ.

Is the Shogurai the same watch as the Seiko Samurai?
It is Seiko’s redesigned Samurai, and the community named it the Shogurai. It is not the earlier, larger Samurai — the RS1719 is cut for the SRPL11, SRPL13 and SRPL15 case, so it is not the strap for an older one.

What is FKM rubber?
Fluororubber. It’s soft and flexible but strong, comfortable enough for everyday wear, and durable — and unlike conventional rubber it doesn’t carry the usual rubber odour.

Are the end links really steel?
Yes — solid stainless steel, brushed, on a 20mm female end link.

Does a clasp come with it?
Yes — the strap ships with the folding clasp shown in the photographs. B1420 and B0797 are there only if you would rather swap it.

What size clasp does it take?
16mm — that’s where the taper finishes. It starts at 20mm where it meets the lugs.

Should I get this or the Hexad bracelet?
Both fit the same three references on the same end link. The RS1719 is the lighter, more comfortable option that keeps the integrated look; the Hexad is full steel. Plenty of people end up with one of each, since swapping between them is a two-minute job on drilled lugs.

Note: The watch shown in the photographs is not included.