CASIO G-SHOCK GA-B2100BEG-1ADR 2100 SERIES TOUGH SOLAR BLUETOOTH ANALOG-DIGITAL BLACK ELECTRO GREEN WATCH

The GA-B2100BEG-1ADR is the Black and Electro Green colourway on G-Shock's most iconic modern silhouette — the octagonal 2100 Series, universally recognised for its slim profile and clean lines.

Module 5689 combines Tough Solar power (no battery changes, approximately 7 months on a full charge), Bluetooth smartphone link via the CASIO WATCHES app, Carbon Core Guard structure for enhanced shock protection, hand shift, and a double LED Super Illuminator that lights both the analog face and the digital display independently. The carbon and bio-based resin case delivers the 2100 Series' signature octagonal geometry with reduced environmental impact. World time covers 38 cities with auto DST switching, the 1/100-second stopwatch includes lap and split modes, and app-configurable reminders can push alerts to the watch for events and tasks. What you get here instead is the slimmest profile, the longest solar run time, and the most universally wearable silhouette in the G-Shock range. 200-metre water resistance, Neobrite hands, and a 145–215mm band.

At a Glance

Why You'll Love It

• At 11.9mm thin and 52 grams, this is one of the slimmest and lightest G-Shocks available — it slides under shirt cuffs, sits flat against the wrist, and wears more like a fashion watch than a tool watch. The octagonal silhouette is the reason the 2100 Series became a global phenomenon.
• Tough Solar eliminates battery replacements entirely. Charge from any light source.
• It's the reason the 2100 Series achieves G-Shock toughness at 11.9mm thin.
• Bluetooth auto time sync keeps the watch accurate without any user input — connect once to the CASIO WATCHES app and the time stays perfect.
• The octagonal bezel shape is the most fashion-crossover G-Shock design — it's been adopted by streetwear, menswear, and even suited contexts that traditionally rejected G-Shock's chunky round silhouettes.

Perfect For

Key Features

• Octagonal 2100 Series silhouette at 11.9mm thin — The signature G-Shock design that broke the mould — an octagonal bezel in the slimmest G-Shock profile category. The slim profile is what makes this the G-Shock that works with everything.
• Tough Solar — no battery replacement — Solar-rechargeable cell with approximately 7 months of normal operation on a full charge. Power save mode extends to approximately 18 months. Battery level indicator on the dial subdial at 9 o'clock.
• Carbon Core Guard structure — A carbon fibre reinforced case surrounds the module, providing G-Shock-level shock protection inside the ultra-slim 11.9mm profile. This is the structural engineering that makes the 2100 thin without being fragile.
• Bluetooth smartphone link — Auto time sync, approximately 300 world time cities, app-configurable reminders, phone finder, and easy watch settings via the CASIO WATCHES app. Note: no smart notifications and no step counter on this model.
• Hand shift feature — Analog hands retract when accessing digital functions, clearing the LCD at 6 o'clock. Essential for readability on an analog-digital at this size.
• Double LED Super Illuminator — Separate LEDs for the analog face and digital display, with selectable duration (1.5s or 3s) and afterglow. White light.

Technical Specifications

Best Matched With

Frequently Asked Questions

Why Buy from City Chain Singapore