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If you want a lighter, more compact G-SHOCK, start with the GMA-P2100: Casio lists it at 40 g and 40.2 mm wide. The GMA-S2100 is a close alternative with the familiar octagonal GA-2100-style design, measuring 42.9 mm wide and weighing 41 g. These specifications make both worth considering for smaller wrists, but they cannot guarantee how either watch will fit you.
Compact G-SHOCK specifications at a glance
The dimensions and weights below are manufacturer specifications from Casio product listings, not independent measurements. Band-size ranges are compatible band measurements listed by Casio; they are useful for narrowing options, not a guarantee of fit on a particular wrist.
| Model | Case dimensions (L × W × H) | Weight | Compatible band size | Design and materials |
|---|---|---|---|---|
| Casio GMA-P2100 | 46 × 40.2 × 11.2 mm | 40 g | 145–190 mm | Analog-digital; resin and bio-based resin case and bezel, with a bio-based resin band, as described by Casio |
| Casio GMA-S2100 | 46.2 × 42.9 × 11.2 mm | 41 g | 140–205 mm, in Casio’s Europe listing | Octagonal analog-digital design; carbon/resin case and bezel with a resin band, as described by Casio |
Casio does not state publication dates for the cited product specifications. The GMA-P2100’s listed battery life is approximately three years on one CR1025 battery. Both models are specified as water resistant to 200 m (20 bar); this is a manufacturer rating, not a recommendation for a particular activity.
Which model should you choose?
Choose the GMA-P2100 for the narrower, lighter option
At 40.2 mm wide and 40 g, the GMA-P2100 is the narrower and marginally lighter of these two choices. Casio describes it as compact and says its band is resized for slimmer wrists. Its compatible band-size range is 145–190 mm, so compare that range with your wrist and the fit you prefer before buying.
#1 Best Overall
- Case size (L× W× H): 46 × 40.2 × 11.2 mm
Choose the GMA-S2100 for the octagonal GA-2100 look
The GMA-S2100 keeps the octagonal analog-digital styling associated with the GA-2100 in a downsized model. It is 42.9 mm wide and weighs 41 g, so it is wider and one gram heavier than the GMA-P2100. Casio’s Europe listing gives a compatible band-size range of 140–205 mm. Casio’s 2022 catalog describes the GMA-S2100 family as “Compact Models Offering an Easy Fit on the Wrist.”
How to judge whether a G-SHOCK will fit your wrist
Case width is a useful first comparison, but it does not tell the whole fit story. Both watches are about 11.2 mm thick; the case’s length, the way the band joins the case, band adjustment and your wrist shape also affect how a watch sits. The specifications do not establish how either model will look or feel on an individual wrist.
Rank #2
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- The rugged watch's 45.4mm case is expertly crafted from fine resin mixed with carbon fiber, an innovative composition that is lighter and more durable than resin
- The smooth black dial features an analog-digital display and double LED light feature, for easy visibility in the dark
- Compare the listed band-size range with your wrist measurement, while allowing for your preferred tightness and how the band is adjusted.
- Check the dimensions of a watch you already own that fits comfortably, especially its width and length, rather than relying on a universal definition of “small wrist.”
- Confirm the exact model suffix and regional listing. Color variants and regional product pages can differ, so check the current local specification page for the precise watch you intend to buy.
What else to know before buying
Casio lists standard G-SHOCK functions for the GMA-S2100 family, including shock resistance, a stopwatch, countdown timer and alarms. The material descriptions above are Casio’s own specifications; they are not an independent environmental assessment. Prices, stock and color availability can change, so check a current local retailer or Casio listing before purchase.
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Best Value
- Casio G-Shock Alarm World Time Quartz Analog-Digital Ladies Watch GMA-P2100ST-4ADR
Rank #4
- ●Impact-resistant structure
Rank #3
- This high-quality watch has a black plastic strap (21 cm length and 20 mm width) with a pin buckle
- Case diameter: 40 mm, case height: 11 mm, case colour: black. Dial colour: black
- Waterproof: 20 bars -Weight: 42 g
- International products have separate terms, are sold from abroad and may differ from local products, including fit, age ratings, and language of product, labeling or instructions.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
