# Casio G-Shock GMA-S2100 White Review by A.I. WatchMetrics

## Watch Summary
The Casio G-Shock GMA-S2100 White is a slim, ultra-lightweight analog-digital sports watch in the iconic octagonal "CasiOak" design made from bio-based resin, targeting active wearers with smaller wrists who want maximum toughness and functionality without bulk, highlighted by Tough Solar quartz movement offering up to 6 months power reserve, 200m water resistance, world time for 31 zones, five alarms, stopwatch, countdown timer, and double LED light.

## Overall Watch Rating: 6.8/10.0

**Functions Metric (9.5/10.0)** - Loaded with world time, five alarms, stopwatch, timer, and auto light, it matches the utility of pricier multifunction quartz like the Citizen Promaster Eco-Drive.
**Movement Metric (8.6/10.0)** - Tough Solar quartz delivers reliable ±15 seconds/month accuracy and 6-month reserve in a shock-resistant package, outperforming basic quartz in entry-level Seikos.
**Versatility Metric (8.5/10.0)** - Excels across casual, sports, travel, adventure, and tool scenarios with its slim profile and resin strap, similar to the adaptable Timex Ironman.
**History & Innovation Metric (8.2/10.0)** - Builds on G-Shock's 40-year legacy of unbreakable watches with bio-resin and Carbon Core Guard structure, akin to the original DW-5600's impact.
**Dials & Design Metric (7.8/10.0)** - Clean white octagonal dial with bold markers offers legible style inspired by luxury but executed in tough resin, better than generic digital Casios.
**Complications Metric (6.5/10.0)** - Stopwatch, world time, and alarms provide solid utility comparable to mid-tier quartz chronos like the Fossil Machine.
**Material Metric (5.5/10.0)** - Bio-based resin case with mineral crystal and basic finishing holds up to abuse like other G-Shocks but trails steel divers such as the Seiko SKX.
**Brand Metric (5.2/10.0)** - Casio G-Shock stands as a mid-tier tough watch leader with enthusiast appeal, on par with Citizen's reliable lineup.
**Rarity Metric (1.0/10.0)** - Mass-produced at retail around $110 with high availability on Chrono24, as common as basic Timex models.

## Total Performance Score (TPS): 5.9

## WM Collector Grade: B

## Performance Insights: Exceptional functions, movement reliability, and versatility drive strong value, far exceeding expectations for the price despite low rarity and material scores.

## TPS Interpretation: Good Value: The watch punches well above its weight in durability, features, and everyday utility compared to peers at this price.

## Watch Data
[https://gshock.casio.com/us/images/product/01/GMA-S2100-4A_main.jpg] - front; [https://gshock.casio.com/us/images/product/01/GMA-S2100-4A_back.jpg] - back; [] - none; [CasiOak Mini] - CasiOak Mini; [Casio] - Casio; [G-Shock GMA-S2100 White] - G-Shock GMA-S2100 White; [Japan] - Japan; [https://gshock.casio.com/us/watches/gshock/product.GMA-S2100-4A/] - https://gshock.casio.com/us/watches/gshock/product.GMA-S2100-4A/; [] - ; [Quartz] - Quartz; [Module 5611] - Module 5611; [0] - 0; [Slimline octagonal G-Shock with Tough Solar, analog-digital display, bio-based resin case, 200m WR, world time, alarms, and stopwatch for active lifestyles.] - Slimline octagonal G-Shock with Tough Solar, analog-digital display, bio-based resin case, 200m WR, world time, alarms, and stopwatch for active lifestyles.; [42.2] - 42.2; [46.2] - 46.2; [11.2] - 11.2; [22] - 22; [200] - 200; [6 months] - 6 months; [N/A] - N/A; [Double LED Super Illuminator] - Double LED Super Illuminator; [0] - 0; [Bio-based resin] - Bio-based resin; [Mineral glass] - Mineral glass; [Fixed resin octagonal] - Fixed resin octagonal; [Solid resin] - Solid resin; [Push button] - Push button; [Resin] - Resin; [Octagonal] - Octagonal; [White analog-digital] - White analog-digital; [yes] - yes; [yes] - yes; [no] - no; [no] - no; [yes] - yes; [no] - no; [no] - no; [no] - no; [no] - no; [yes] - yes; [no] - no; [no] - no; [no] - no; [no] - no; [yes] - yes; [no] - no; [no] - no; [no] - no; [no] - no; [no] - no; [yes] - yes; [no] - no; [yes] - yes; [yes] - yes; [yes] - yes; [yes] - yes; [yes] - yes; [no] - no; [no] - no; [no] - no; [no] - no; [no] - no; [no] - no; [no] - no; [no] - no; [5.9] - 5.9; [B] - B; [185] - 185;

**A.I. WatchMetrics Review v37.4 Grok 4 Fast. December 19, 2025.**