Explorer 36mm Titanium Polished — Ultra Thin Watch Case

New to Seiko modding? Here's everything you'll need for a complete, functioning watch — in the order you'd actually assemble it.

What's already in this purchase:

The Explorer 36mm titanium case body with the flat AR-coated sapphire crystal pre-fitted, the solid titanium caseback, and the titanium coin-edge screw-down crown. That's the foundation. Everything below is what you'll add to make a wrist-ready watch.

The 4 parts you'll need for a complete watch:

1. Chapter ring — required first. The chapter ring seats the dial at the correct height; without it, the dial sits too low and the hands won't clear.
   (SKX013-spec — sold on a separate page. See the "sold separately" panel above for normal vs ultra thin guidance.)
   Browse compatible chapter rings
2. Dial (28.5mm) — the face of the watch. The biggest aesthetic choice you'll make. Match it to your chosen movement (date / day+date / no-date dial).
3. Hands — paired with your dial. Most modders match lume colour across both hands and dial markers (BGW9 white-blue, C3 green, etc.). Our Swiss Super-LumiNova® BGW9 hands pair especially well with the Explorer silhouette.
4. Movement — NH35 (date), NH36 (day+date), NH38 (no date), or source your own. The movement is the engine of the watch.

Optional finishing touches:

1. Bracelet (20mm lug) — fits all our 316L steel bracelets, but for a build that's all-titanium end-to-end we recommend our Seikonaut Bracelet in Titanium . Matched finish, matched material, matched weight philosophy.
2. Strap (20mm lug) — the titanium build pairs especially well with luxurious leather. We recommend our shell cordovan straps for a refined wear, plus full-grain cowhide options for more casual builds.

Want it built for you?

Tick the Assemble Watch (+SGD $50) option above on this page and we'll handle the full build in our Singapore workshop — case fitting, movement seating, crown alignment, caseback press, and function check.

Heads up: assembled watches require 2–5 business days of workshop time before shipping.

Once your parts arrive, see the How To Mod tab for assembly tutorials.

1. 1x Watch Case Body in Grade 4 Titanium, Polished (with pre-fitted flat AR-coated sapphire crystal)
2. 1x Titanium Coin-Edge Screw-Down Crown
3. 1x Solid Titanium NH Caseback

All photos of watches with modification parts are for illustration purposes only and are not included with the case purchase.

Do I need to remove the sapphire crystal to install the chapter ring?
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.)

How does titanium compare to steel for a watch case?
On this case, three differences matter. Weight: the titanium build is 18.5 grams complete, versus 30.2 grams for the 316L steel sibling — about 40% lighter. Hardness: Grade 4 Titanium is actually harder than 316L stainless steel, so it's more scratch-resistant, not less (the common assumption goes the other way). Skin contact: titanium is hypoallergenic and entirely corrosion-resistant, so it won't react with sweat or skin oils the way some steels can over time.

Why Grade 4 specifically?
Grade 4 is the strongest of the commercially pure titanium grades — pure titanium, no alloying elements, but with controlled oxygen and iron content that pushes its strength and hardness above the other pure grades. It's the same grade used in aerospace structural components and surgical implants. It also polishes to a higher lustre than the lower grades, which is what makes the Polished version of this case possible.

Will polished titanium look different from polished steel?
Not visibly. Polished 316L stainless steel and polished Grade 4 Titanium are essentially indistinguishable to the eye on the wrist — the reflectivity, colour temperature, and finish read identically. The product photos include side-by-side reference comparisons. The difference shows up the moment you pick it up.

Will my existing 316L steel bracelets fit this case?
Yes — the Explorer 36mm Titanium Polished uses the same 20mm lug width as our standard cases, so any of our 316L steel bracelets fits. That said, for a build that's all-titanium end-to-end — matched finish, matched material, matched weight philosophy — our Seikonaut Bracelet in Titanium is the natural pairing. A polished titanium bracelet keeps the case's weight advantage; a steel bracelet adds back some of the weight you saved by going titanium in the first place.

Should I choose the normal or the ultra thin chapter ring?
The choice depends on your dial, not the case — both sizes fit this 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.

Does this case need a chapter ring?
Yes. The Explorer 36mm Titanium Polished requires an SKX013-spec chapter ring — sold separately. The chapter ring seats the dial at the correct height; without it, the dial drops and the hands will not clear properly.

What's the difference between TYPE M and TYPE L?
Type M and Type L are Seiko's two factory hand-fitting versions of the NH series. Type L sits higher than Type M — about 0.4mm taller from base to second-hand pinion. Because of the tight clearance between hands and sapphire in this Ultra Thin case, only Type M will fit. Confirm your movement type before ordering.

Will SKX007 dials fit?
Any 28.5mm dial will fit. Stock SKX007 dials may seat differently because the original SKX007 has a 4 o'clock crown position with offset dial feet, while our case is designed for 3 o'clock dial feet.

1. A Complete Guide On How To Mod Your SEIKO Watch Dial And Hands (Photos & Video)
2. Fitting dials with four dial legs
3. Seiko Modding: The Complete Build Guide (2026)