SKX013 Flat Sapphire Crystal

Name: SKX013 Flat Sapphire Crystal
Brand: Lucius Atelier
SKU: skx013_flat_dsb
Price: 57.0 SGD
Availability: OutOfStock

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$47 SGD - $57 SGD

AR Coating Surface

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Single Sided sold out

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The Flat Sapphire. OEM Dimensions. For the SKX013.

Sapphire sits second only to diamond on the Mohs scale — it shrugs off the scratches a stock crystal collects. This one is cut to OEM dimensions — 28mm across, 2.8mm thick — so it drops into the SKX013 exactly where the stock crystal sat, and keeps the original low profile.

The flat profile is the original look: low, clean, nothing announcing itself. Choose single- or double-sided anti-reflective coating, in clear or blue — every coated face carries at least three layers, so what you see is the dial, not the room behind you.

The stock look, minus the scratches.
OEM dimensions, sapphire hardness.

Second to diamond.
Sapphire ranks just under diamond on the Mohs scale — the scratches that dull a stock crystal simply don't land.

Single or double AR.
Anti-reflective coating on the underside alone, or both faces — in clear or blue.

OEM profile.
Same 28mm × 2.8mm as the stock crystal — the original low look, in harder glass.

Fits the SKX013 family.
SKX013, SKX015, SKX017 and all 7S26-0030 cases. Seats with a crystal press.

Heads up — fit & install

Fits the SKX013, SKX015, SKX017 and all 7S26-0030 cases. Seats with a crystal press — there's no safe press-free way to seat a sapphire; if you don't own a press, a watchmaker or mod specialist fits it in minutes. A crystal gasket is required but not included — the crystal seats with the gasket already in your case. Gaskets are cut to match a specific case, and ours are cut for our cases, so one from us would not seal a stock Seiko case correctly. If the gasket in your case is hardened, cracked or deformed, fit a replacement matched to your case reference — any Seiko parts supplier stocks them. (New gaskets come fitted only with our watch cases.)

New to this? The sapphire crystal install guide walks through it.

Specs
What's Included
Fitment
How To Mod

Specs
1. Quality Swiss Production Quality, ISO 9001 Certified
2. Material Sapphire
3. Crystal Shape Flat (OEM Dimension)
4. Crystal Diameter 28mm (OEM Dimension)
5. Crystal Thickness 2.8mm (OEM Dimension)
6. Crystal Dome Height Not Applicable
7. Anti-Reflective Coating Surface Single Side (Underside) or Double Side (Topside and Underside)
8. Anti-Reflective Coating Color Clear, Blue
9. Tint Clear AR: Colorless. Blue AR: Slightly brown.
10. Optical Distortion None
11. Fit Models SKX013, SKX015, SKX017 and all 7S26-0030 Watch Cases
1. 1x Sapphire Crystal
2. Gasket not included — a crystal gasket is required; your case's existing gasket is reused. Gaskets are cut to match a specific case, so ours ship fitted with our watch cases only; if yours is worn, source a replacement matched to your case reference.
All photos of watches with modification parts are for illustration purposes only and are not included with the sapphire crystal purchase.
Fits the SKX013, SKX015, SKX017 and all 7S26-0030 cases.

Seats with a crystal press — see the install guide under How To Mod.

Pairs with:
1. SKX013 Bezel Inserts
2. SKX013 Bezels
1. How To Modify Your SEIKO Watch — Sapphire Crystal
2. Seiko Modding: The Complete Build Guide (2026)

Are sapphire crystals really scratch-proof?

Effectively, yes, for daily wear. Sapphire ranks second only to diamond on the Mohs hardness scale, so keys, desk edges and door frames simply don't leave a mark. Only diamond — or another material approaching its hardness — can scratch it. That's why every crystal we make is sapphire rather than mineral glass.

Flat or double domed — which sapphire should I choose?

Flat is the low-profile, original-style look. Double domed curves on both the top and the underside — it catches light differently across the dial and gives the watch a warmer, vintage character. Neither is tougher than the other; both are sapphire. It's a styling call.

What's the difference between single-sided and double-sided AR coating?

It's which faces carry the anti-reflective layers. Single-sided AR is applied to the underside only; double-sided coats both the topside and underside for maximum clarity — noticeably fewer reflections between you and the dial. Every coated face carries at least three AR layers. Some of our crystals also come uncoated, if you prefer the bare sapphire look.

Blue or clear AR coating — what's the difference?

The colour of the reflection, not the clarity. Clear AR is colourless — reflections just disappear. Blue AR kills glare the same way but flashes a subtle blue at an angle, with a slightly brown tint face-on (a standard characteristic of all blue AR). Both do the same optical job; pick the look you prefer.

Will an SKX007 crystal fit an SKX013?

No — the diameters are different, so they aren't interchangeable. The SKX007 family (7S26-0020, plus SRPD/SRPE) takes a 31.5mm crystal, the SKX013 family (7S26-0030) takes 28mm, and Seiko 5 SNK models take 30mm. Match the crystal to your case and check the Fit Models line in the Specs before ordering.

Do I need a crystal press to install a sapphire crystal?

Yes. A crystal press seats the sapphire straight and evenly — there's no reliable press-free method that doesn't risk cracking the crystal or breaking the water seal. If you don't own a press, a watchmaker or watch-mod specialist can fit it in minutes.

Do sapphire crystals come with a gasket?

No — the crystal ships on its own, with no gasket in the box. You do need a crystal gasket to install it, but in practice that's already sorted: the crystal seats with the gasket that's in your case, so you simply reuse the existing one. We don't sell gaskets separately because a gasket is cut to match one specific case — ours are cut for Lucius Atelier cases, so a gasket from us would not seal a stock Seiko case correctly. New gaskets come fitted only with our watch cases. If the gasket in your case is hardened, cracked or deformed, replace it with one matched to your case reference — any Seiko parts supplier stocks them.