Casio presents GSTB300, the latest addition to the G-STEEL line of G-SHOCK shock-resistant watches. The GSTB300 is the first G-STEEL watch with a front button, which adopts a new Carbon Core Guard structure that delivers superior shock resistance by leveraging the lightness and outstanding rigidity of carbon fiber.

For the GST-B300 with front button design, Casio developed a new Carbon Core Guard structure, which protects the module with a carbon case. Highly durable carbon fiber-reinforced resin is added not only to the center case, but also to the front and side button guards, providing even stronger resistance to shocks from above or below, or from any side.

The battery indicator at the 6 o’clock position, designed to evoke a brake disk, shows the remaining battery power by an arrow pointer and a curved red bar, providing visually interesting ways to check the battery.

As for functions, in addition to automatic time adjustment via Bluetooth® when paired with a dedicated smartphone app, the watch features world time setting for over 300 cities as well as various alarm and countdown timer settings, all easy to use. It is also equipped with other practical functions such as the Tough Solar, solar charging system developed by Casio, and a high luminosity full auto double LED light.

Technical details

Construction: Shock-resistant
Water Resistance: 200 meters

Standard Bluetooth® low energy
Signal Range: Up to 2 meters (may differ depending on surrounding conditions)

World Time
39 time zones (39 cities + coordinated universal time), daylight saving on/off, auto summer time (DST) switching, home time/world time swapping

Measuring capacity: 00’00”000~59’59”999 (for the first 60 minutes), 1:00’00”0~23:59’59”9 (after 60 minutes); measuring unit: 1/1000 second (for the first 60 minutes), 1/10 second (after 60 minutes); measuring modes: elapsed time, split time

Countdown Timer
Measuring unit: 1/10 second (maximum 24 hours)

5 multi-function alarms (with daily, 1 time, schedule); hourly time signal

Other Features
Mobile Link functions (world time: over 300 cities, automatic time adjustment, easy watch setting, phone finder); hand shift feature; 12/24-hour format; button operation tone on/off; full auto-calendar; battery level indicator; full auto double LED light (Super Illuminator with afterglow: 1.5/3.0 seconds)

Power Source
Tough Solar power system (solar-charging system)

Continuous Operation
About 19 months with the power-saving function ON after full charge

Size of Case
51.0 × 50.0 × 15.5 mm

Total Weight
Approx. 82g