Chapter Rings

The chapter ring is the ring that sits between the dial edge and the case, carrying the minute and hour markings around the dial. On SEIKO's SKX models it's a plastic part from the factory; ours is machined brass with printed markings for a crisper, more finished look. Swapping it is one of the simplest cosmetic upgrades in a Seiko mod — a small part with a big effect on how sharp the dial side reads.

Yes — it's made for the SKX013 and also fits the SKX015, SKX017, all 7S26-0030 watch cases, and our own cases. Dimensions are customised over the OEM ring for greater clearance and a clean pairing with our dials.

Yes — it's a direct replacement for the SKX007's original plastic chapter ring, sized as original. It also fits the SKX009, SKX011, SKX171, SKX173, SKX175, our 42mm Diver's watch case, and all 7S26-0020 watch cases.

The choice depends on your dial, not the case — both sizes fit every Ultra Thin Edition case. If your dial has applied (raised) indices, the ultra thin chapter ring is the better choice because its slimmer profile gives the indices clearance instead of resting on top of them. If your dial is flat-printed (no applied markers), either size works. When in doubt, the ultra thin chapter ring is the safer default because it works with both dial types.

The ring carries a 24-hour numeral track in place of the standard markers. Paired with the Seiko NH34 GMT movement, the NH34's fourth hand reads against this track to show a second time zone. On a standard three-hand movement the track is purely decorative — the ring fits the same, but there's no 24-hour hand to read it, which is why we recommend it with the NH34.