Features
G-STEEL
Carbon Core Guard structure
From G-SHOCK, the watch brand that is constantly setting new standards for timekeeping toughness, come new G-STEEL models that boast a new shock resistant Carbon Core Guard structure.
The case is made of fine resin that incorporates carbon fiber for light weight along with rigidity that is superior to that of resin. This material protects the internal module from shock-induced damage and deformation. The dual back cover protects the back surface against impact. The small case of the GST-B100 series base model provides a comfortable fit, even though the watch is equipped with a wide face.
The light-on-dark LCD contributes to both functionality and face design.
Smartphone Link
• Approximately 300 World Time cities
• Alarm
• Timer
• Hand alignment correction
• Time swapping
• Phone Finder
Tough Solar
Super Illuminator (double) with Full Auto light illuminates the face and digital display

* Compared to the GST-B100 series, the 12-6H is 4.8 mm thinner, while the 3-9H is 4.6 mm thinner.

Carbon Core Guard structure
A new shock-resistant Carbon Core Guard structure integrates the case. An external structure capitalises on its toughness and lightness.

Super Illuminator (high-brightness LED)
The Super Illuminator function lights up the dial and LCD with high-intensity lights, maintaining watch readability in the dark.
 
Specifications
Case / bezel material: Carbon / Stainless steel
Resin Band
Mineral Glass
Neobrite
Shock Resistant
Carbon Core Guard structure
200-meter water resistance
Double LED light
LED light for the face (Full auto LED light, Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds), afterglow)
LED backlight for the digital display (Full auto LED light, Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds), afterglow)
Tough Solar (Solar powered)
Mobile link (Wireless linking using Bluetooth®)
World time
39 time zones* (39 cities + coordinated universal time), daylight saving on/off, auto summer time (DST) switching, Home city/World time city swapping
*May be updated when connected to a smartphone.
1/1000-second stopwatch
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
Countdown range: 24 hours
Countdown start time setting range: 1 second to 24 hours (1-second increments, 1-minute increments and 1-hour increments)
5 multi-function alarms (with daily, 1 time, schedule)
Hourly time signal
Hand shift feature (Hands move out of the way to provide an unobstructed view of digital display contents.)
Battery level indicator
Full auto-calendar (to year 2099)
12/24-hour format
Button operation tone on/off
Power Saving (display goes blank and hands stop to save power when the watch is left in the dark)
Regular timekeeping
Analog: 3 hands (hour, minute (hand moves every 10 seconds), second), 
Digital: Hour, minute, second, pm, month, date, day
Accuracy: ±15 seconds per month (with no mobile link function)
Approx. battery operating time:
6 months on rechargeable battery (operation period with normal use without exposure to light after charge)
20 months on rechargeable battery (operation period when stored in total darkness with the power save function on after full charge)
 
Size of case / Total weight
Size of case : 53.3×49.2×14.5mm
Total weight : 87g