Casio
Casio G-Shock GM-2100 Strap Size & Fitting
The Casio G-Shock GM-2100 uses an integrated / proprietary fitting, not standard lugs — so it needs G-Shock GM-2100-specific straps or an adapter kit.
Lug fittingIntegrated
| Strap fitting | Integrated / proprietary |
|---|---|
| Case size | 44.4 mm |
| Lug-to-lug | 48.5 mm |
| Thickness | 12.8 mm |
Strap styles that fit
- Brand / OEM strapMade for this exact model.
- Adapter + standard strapBuy a model-specific adapter first.
- NATO / pass-throughNo standard lugs to pass through.
- 2-piece leatherNeeds an adapter to fit.
- Rubber / FKMOEM or adapter only.
- Metal braceletModel-specific bracelet only.
▲ Metal-bezel CasiOak; GA/GM-2100 adapters needed.
Fit & sizing notes for the G-Shock GM-2100
- What to buy: straps made for the G-Shock GM-2100, or an adapter kit for this exact model. A normal-width strap won't attach on its own. Our integrated & smartwatch strap guide explains the options.
- Adapters stick out past the case, so the watch wears longer; check the adapter's output width before buying straps for it.
- Wrist fit: at 48.5mm lug-to-lug it should sit within the top of wrists from about 16.2cm up (rule of thumb: lug-to-lug under ~30% of wrist size). That's longer than 77% of the watches in our index. See what size watch suits your wrist.
- Strap thickness: at 12.8mm thick it's a chunky case: thicker padded leather, rubber/FKM or a heavier NATO balance it visually; very thin straps can look undersized.
Sources & corrections
Lug width from widely published specifications. Case sizes and references vary, so measure your own watch if anything looks different.
Spec wrong for your watch? Send us a correction with your reference number.
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Casio G-Shock GM-2100 — strap questions
What strap size does the G-Shock GM-2100 take?
The Casio G-Shock GM-2100 doesn't use standard spring-bar lugs — it has an integrated/proprietary fitting, so you need G-Shock GM-2100-specific straps (or, where one exists, an adapter kit) rather than a normal strap.
Can I put a normal NATO or leather strap on it?
Not directly. A standard strap won't attach on its own. Where a model-specific adapter exists, fit that first and then a normal strap of the adapter's width.
Where can I buy straps that fit the G-Shock GM-2100?
Search for straps and adapters made specifically for the Casio G-Shock GM-2100; generic sizes won't clip in without one.