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Casio’s G-SHOCK GMB2100GD-9A (also designated GM-B2100GD-9A) gives the full-metal 2100 its most conspicuous finish yet: yellow-gold ion-plated stainless steel over the familiar octagonal “CasiOak” design. It is not a solid-gold watch. The appeal is the combination of jewelry-like color, Tough Solar charging, Bluetooth connectivity, shock resistance and a 200-meter water-resistance rating in a substantially heavier bracelet watch.
Casio announced the model on February 21, 2023. The Japanese release followed on March 10 at ¥80,300 including tax, while European availability was scheduled for April at a €599 MSRP. Those are launch-market figures, not a confirmed universal 2026 price.
What the GMB2100GD-9A actually is
The standard reference is GM-B2100GD-9A; Casio’s U.S. shopping page compresses it to GMB2100GD-9A, and the European regional reference is GM-B2100GD-9AER. It is a full-metal member of the 2100 family: an analog-digital G-SHOCK with a stainless-steel case, bezel and bracelet, finished in yellow-gold ion plating.
“All-gold” describes the appearance and plated exterior, not precious-metal content. The underlying watch is stainless steel, and its movement is quartz with solar charging and smartphone-linked functions rather than a mechanical luxury caliber.
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![Casio GM-B2100GD-9AJF [G-Shock (G-Shock) Full Metal Model with Smartphone Link GM-B2100 Yellow Gold Color Model] Watch Japan Import March 2023 Model](https://m.media-amazon.com/images/I/51R5kAE7MML._SL160_.jpg)
- G-SHOCK is a shock-resistant clock that builds a new concept of toughness on the watch. It is a full metal model equipped with a smartphone link in the digital/analog combination ''GA-2100'' series developed after inheriting the concept of the first model DW-5000C.
- [Shock-resistant structure] G-SHOCK's core technology in pursuit of toughness is resistant to shocks that protect the module with a unique uneven shape, preventing direct impact on glass & buttons.
- [20 aThesis waterproof] A variety of places & situations can be used, such as daily water work, swimming, surfing, jet skiing, etc.
- [Mobile link function] Compatible mobile phones can be linked by Bluetoothⓡ communication.
- [Other product specifications] Tough solar/needle evacuation function/World time/stopwatch/timer/time alarm/battery indicator display/power saving function/full auto calendar/12/24 hours display switching/operation sound ON/OFF switching/date switch/date Display / day display / double LED light
The 2100 story began with the resin GA-2100 in 2019. Casio introduced the full-metal GM-B2100 platform in 2022, replacing the resin exterior with steel. The GD-9A is therefore a new colorway and positioning of an existing platform, not a new movement or radically different case architecture.
Casio’s U.S. product page lists the model and an online purchase route; the accessible page does not establish a current U.S. dollar MSRP.
Design and the meaning of “gold”
The watch keeps the 2100’s faceted octagonal bezel and compact analog-digital layout. A black dial supplies contrast for the gold-toned hands, indexes and accents, so the result is not a featureless gold block.
Rank #2
- Go metal-clad with this Casio G-Shock Analog-Digital watch in an ever-popular color scheme of black and gold
- Metal bezel ion-plated in gold and set against a black base is a stylish design choice
- battery life: 3 years on SR726W X 2Casio G-Shock Style #: GM-2100G-1A9
Case, bezel and bracelet are stainless steel. Casio applies yellow-gold ion plating to the visible exterior, including smaller components such as buttons and screws. The international product description also highlights contrasting bezel treatments: circular hairline finishing on the top surface and polished, mirror-like bevels and raised areas.
The bracelet is solid stainless steel with a one-touch three-fold clasp. A screw-lock caseback and mineral glass complete the construction. Plating can be scratched at high-contact points; if a deep scratch reaches through the finish, the steel underneath can become visible. That is a general consideration for plated steel, not a verified failure rate for this specific reference.
In practical terms, this is a dressier, fashion-led G-SHOCK—not a precious-metal dress watch. It does not offer the solid-gold content, sapphire crystal or traditional mechanical finishing associated with conventional luxury watches.
Rank #3
- Durable and Elegant Design: Gold ion-plated stainless steel bezel with a bio-based resin case offers durability and a sophisticated look.
- G-SHOCK Toughness: Features shock resistance and 200-meter water resistance, ideal for extreme environments.
- Advanced Timekeeping: Includes world time with 31 time zones, 5 daily alarms, and a full auto-calendar to 2099.
- Precision Performance: Equipped with a 1/100-second stopwatch, countdown timer, and target time alarm for versatile functionality.
- Long Battery Life: Powered by a 5-year CR2016 battery, designed to endure.
Specifications and functions
| Specification | GMB2100GD-9A detail |
|---|---|
| Case dimensions | 49.8 × 44.4 × 12.8 mm |
| Weight | 165 g |
| Case and bezel | Stainless steel with yellow-gold ion plating |
| Bracelet | Solid stainless steel; one-touch three-fold clasp |
| Crystal | Mineral glass |
| Caseback | Screw-lock |
| Water resistance | 200 meters / 20 bar official rating |
| Power | Tough Solar |
| Runtime | Approximately seven months without further light exposure; approximately 18 months in power-saving storage after a full charge |
| Accuracy | ±15 seconds per month without mobile-link correction |
| Phone connection | Bluetooth Mobile Link through the CASIO WATCHES app |
| World time | 38 cities/time zones plus UTC on the watch; approximately 300 cities available through the app |
| Alarms | Five daily alarms plus hourly signal |
| Timer | One-second increments, maximum 60 minutes |
| Stopwatch | 1/100-second measurement for the first 60 minutes, then one-second measurement |
| Lighting | Double LED / Super Illuminator |
| Calendar | Full automatic calendar through 2099 |
| Wrist fit | Approximately 150–205 mm compatible band size |
Beyond the gold finish, the platform’s useful upgrades are Tough Solar and Bluetooth. With a compatible phone and the CASIO WATCHES app, the watch can automatically correct the time, change settings, manage world time, set reminders, record time and place, and locate a paired phone. It also includes a battery indicator, hand-shift function and power-saving mode.
The watch remains usable as a standalone timepiece if you never pair it. Automatic correction and app-based controls simply will not be available. Phone compatibility depends on Casio’s supported-device information and can change over time.
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The largest practical difference is mass. Casio’s official comparison lists the full-metal model at 165 g, versus approximately 51–52 g for the resin GA-2100 and related comparison models. That roughly threefold increase changes the wearing experience more than the modest dimensional difference.
Rank #4
- Elegant Design: Features a pearlescent polarized coating on the bezel and band for a soft, sophisticated shine.
- Eco-Friendly Materials: Crafted with bio-based resin components to reduce environmental impact.
- Tough & Durable: Shock-resistant construction and 200-meter water resistance for worry-free adventures.
- Dual LED Light: Equipped with a Super Illuminator LED for the face and digital display, ensuring readability in any lighting.
- Lightweight Comfort: Weighing just 40g, it’s designed for a comfortable fit on wrists measuring 145–190 mm.
| Model type | Construction and size | Power and connection | Best fit |
|---|---|---|---|
| GMB2100GD-9A | Gold-ion-plated steel; 49.8 × 44.4 × 12.8 mm; 165 g | Tough Solar and Bluetooth | Gold styling, bracelet heft and maximum platform features |
| GA-2100 | Resin; approximately 48.5 × 45.4 × 11.8 mm; approximately 51 g | Conventional battery on the cited resin comparison | Lowest weight, lower cost and the core 2100 silhouette |
| GAB2100 | Lighter resin-and-metal construction | Solar/Bluetooth-oriented functionality | Some premium functions without full-metal weight |
The GM-B2100 is only slightly longer than a GA-2100 and remains relatively slim, but a rigid steel bracelet and 165-gram mass make it a fundamentally different proposition. Buyers should choose based on whether they want the metal construction and presence, not merely the same shape in another color.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Launch pricing, availability and model-number traps
Casio announced the watch on February 21, 2023. Japan’s announced release date was March 10, 2023, at ¥80,300 including tax. Europe was scheduled for April 2023 at a €599 MSRP. These figures describe the original launch markets and should not be converted into a single current global price.
As of August 16, 2026, Casio’s U.S. site still showed the model within its 2100 and Black and Gold collections, but the accessible product extract did not expose a current U.S. price. A historical StockX listing may provide a resale-market signal, but it is not Casio pricing and can vary with supply.
Best Value
- Shock Resistant
- 20 bar water resistant
- Stable solar power
- Easy to operate via Smartphone
Check the reference before buying. GM-B2100GD-5A is the rose-gold version; GMW-B5000GD-9 belongs to the square 5000 series; and GA-2100-9A is a yellow resin model. Regional suffixes also differ: the European version adds “ER.”
Who should buy it?
It makes sense for
- Buyers who specifically want a yellow-gold look with a recognizable G-SHOCK silhouette.
- Collectors seeking the full-metal 2100 platform rather than another resin colorway.
- People who value Tough Solar convenience, Bluetooth correction and app controls.
- Wearers who prefer a substantial steel bracelet to a resin strap.
Think twice if you want
- Solid gold or genuine precious-metal content.
- A lightweight watch; the 165-gram specification is far above resin 2100 models.
- Sapphire crystal or a discreet, easily interchangeable everyday style.
- Only basic timekeeping, since the solar-and-Bluetooth premium may add little value for you.
- The prestige, finishing and mechanical character of a traditional luxury gold watch.
The most sensible alternatives
Casio’s U.S. 2100 collection places the relevant options together:
- GMB2100D-1A: the silver full-metal version, generally the least polarizing choice for daily wear.
- GMB2100BD-1A: black ion-plated full-metal styling for a darker, less jewelry-like appearance.
- GA2100-1A1 or GA2100-1A: the lighter, lower-cost route to the 2100 design.
- GAB2100-1A: a lighter resin-and-metal alternative for buyers who want solar/Bluetooth-oriented functions without full-metal mass.
Verdict
The GMB2100GD-9A is best understood as a style-led upgrade to the full-metal 2100 platform. Its strongest case is the mix of yellow-gold visual impact, steel-bracelet presence, Tough Solar, Bluetooth and G-SHOCK shock resistance. Its compromises are equally clear: the gold is plating over stainless steel, the watch is dramatically heavier than a resin GA-2100, the crystal is mineral, and the color is less versatile. Buy it for that specific combination—not as a substitute for a solid-gold luxury watch.
Quick Recap
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.
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