GSTB400CX-1A

G-STEEL
GST-B400 Series
GSTB400CX-1A

Welcome in the Year of the Snake with a special edition G-STEEL crafted at the intersection of metal and resin. Celebrate 2025 with innovative form and design inspired by the ancient ouroboros.

This slim GSTB400 features an ouroboros motif, the ancient auspicious symbol of a serpent eating its own tail, representing infinity and immortality.   
This special timepiece pairs a silver-colored metal bezel and black watch face with gold-colored accents for a design that takes you smoothly from casual settings to formal occasions and back again.  

The side buttons and strip across the face from the 3 o’clock to 9 o’clock position add textural appeal with a snake pattern touch that nods to the Year of the Snake. The case back is engraved with a special ouroboros illustration representing infinite possibility. 

 
The GSTB400 brings together smaller components and a thinner module to deliver an even slimmer profile, while still offering the Bluetooth connectivity and solar power charging you want for greater convenience and significantly less power consumption. Add to this the watch’s Carbon Core Guard structure, and you have the slimmest G-STEEL yet (as of December 2024), measuring just 12.9 mm from case back to bezel top, over a millimeter slimmer than the GSTB100.  

Passionate attention to the smallest details — with large, easy-to-press stainless steel buttons, a resin band, and silver metal case featuring different finishes on the top and middle bezels — achieves an elegant, transformative look worthy of the Year of the Snake.

Case size (L× W× H) 46.6 × 49.6 × 12.9 mm
Weight 86 g
Case and bezel material Carbon / Stainless steel
Band Resin Band
Construction Shock Resistant Carbon Core Guard structure
Water resistance 200-meter water resistance
Power supply and battery life Tough Solar (Solar powered)

Smartphone Link feature Mobile link (Wireless linking using Bluetooth®)
Apps CASIO WATCHES
App connectivity feature
Auto time adjustment
Easy watch setting
Approximately 300 world time cities
Time & place
Reminder
Phone finder

Glass Mineral Glass
Compatible band size 145 to 215 mm
Other Neobrite

World time
World time
38 time zones (38 cities + coordinated universal time), city code display, city name display, daylight saving on/off, auto summer time (DST) switching, Home city/World time city swapping
Stopwatch
1/100-second stopwatch
Measuring capacity: 
00'00''00~59'59''99 (for the first 60 minutes)
1:00'00~23:59'59 (after 60 minutes)
Measuring unit: 
1/100 second (for the first 60 minutes)
1 second (after 60 minutes)
Measuring modes: Elapsed time, lap/split time
Timer
Countdown timer
Measuring unit: 1 second
Countdown range: 60 minutes
Countdown start time setting range: 1 second to 60 minutes (1-second increments and 1-minute increments)
Alarm/hourly time signal
5 daily alarms
Hourly time signal
Light
Double LED light
LED light for the face (Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds), afterglow)
LED backlight for the digital display (Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds), afterglow)
Light color
LED:White
Calendar
Full auto-calendar (to year 2099)
Mute feature
Button operation tone on/off
Energy saving feature
Power Saving (display goes blank to save power when the watch is left in the dark)
Battery display/alert
Battery level indicator
Run time
Approx. battery operating time:
7 months on rechargeable battery (operation period with normal use without exposure to light after charge)
18 months on rechargeable battery (operation period when stored in total darkness with the power save function on after full charge)
Accuracy
Accuracy: ±15 seconds per month (with no mobile link function)
Other features
12/24-hour format
Date/month display swapping
Day display (days of the week selectable in six languages)
Hand shift feature (Hands move out of the way to provide an unobstructed view of digital display contents.)
Regular timekeeping:
Analog: 2 hands (hour, minute (hand moves every 20 seconds)), 1 dial (battery level, mode)
Digital: Hour, minute, second, pm, month, date, day

*This item is BRAND NEW and will come with the original box and papers. We are authorized CASIO dealers, which means you will receive the manufacturer's warranty with your purchase.