G-Shock Solar Powered Blue Tooth Watch. GAB2100-1A

The GA-B2100-1A is a masterclass in Functional Evolution. It retains the slim, octagonal silhouette (11.9 mm) that made the original 2100 a global phenomenon, but it fixes the "wish list" items that fans had for years. By adding Tough Solar and Bluetooth®, Casio turned a lifestyle fashion piece into a professional-grade tool that never needs a battery change and always tells the perfect time.
The "1A" colorway is the most versatile in the lineup. It features a matte black resin case and band with a dark grey dial and white-tipped hands for high-contrast legibility. It’s the "Swiss Army Knife" of watches—equally at home under a blazer or a wetsuit.

Key Performance Features
Tough Solar Power: Converts even weak light from indoor lamps into energy, ensuring the watch remains powered without the need for manual battery replacements.
Smartphone Link (Bluetooth®): Connects to the CASIO WATCHES app for 4-times-daily auto-time adjustment, easy world time settings (300+ cities), and a "Phone Finder" button.
Carbon Core Guard Structure: An internal carbon-fiber-reinforced resin case that protects the module from high-impact shocks while keeping the watch incredibly lightweight (52g).
Auto Double LED (Super Illuminator): Features a high-brightness LED for the analog face and a separate backlight for the digital LCD, with an "Auto-Light" feature that activates when you tilt your wrist.
High-Contrast Analog-Digital: The white hands stand out sharply against the black dial, making it one of the easiest "CasiOaks" to read at a split-second glance.
200m Water Resistance: Fully professional-grade protection—this is a "style" watch that is built for the deep end.
Hand Shift Feature: With the press of a button, the hands move out of the way to provide an unobstructed view of the digital display.

In the Box
G-SHOCK GA-B2100-1A "Tough Solar," Signature G-SHOCK Hexagonal Tin, User Manual, and Warranty.