SKX013 Brushed Ice Blue Chapter Ring - GMT II 24H Numerals — Ultra Thin

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.

A specific size and spec used by Seiko in the SKX013 (discontinued 2019). The LA smaller-case lineup all uses this same spec, which means dozens of chapter ring designs work across every smaller case in the catalogue.

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.

The SKX013's original plastic chapter ring has a protruding pin at its base to lock the hour and minute markers in line with the dial. Our ring does away with the pin — its uniform structure means alignment isn't affected in normal fitting. If you want it locked absolutely solid, a small amount of adhesive can be used to secure the ring's position.

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.

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.

No — and that's the whole point of us pre-installing the sapphire for you. The chapter ring sits on top of the dial inside the case, not under the crystal, so the crystal stays where it is throughout the build. (If you ever do need to remove the sapphire — for example, to replace it — that's a workshop job we handle for you, not an at-home step.)