G-Steel Black on Black GST-B400BB-1AER Watch

The Watch

Casio is renowned for its rugged, impeccably crafted watches. The brand has made its mark in the watchmaking world by introducing a diverse range of feature-packed timepieces. The GST-B400BB-1AER from the G-Steel Black on Black collection is fully equipped to take on any adventure. Its case weighs 80 grams and combines carbon-fiber-reinforced resin with stainless steel for unmatched wrist comfort. Resolutely masculine, its round shape measures 49.60 mm in diameter, 12.90 mm thick, and 46.60 mm in length. The dial is protected by a mineral crystal surrounded by an ion-plated bezel in brushed circular stainless steel, with markings identifying the functions of the four push buttons around the case. The screw-secured case back ensures water resistance of 20 ATM.

The Dial

Designed specifically for athletes, this black dial packs in features you'll love. The analog display features two main hands for hours and minutes, tracking along indexes and a minute track around the dial's perimeter. A digital display is also present, represented by two subdials at 3 and 6 o'clock. To ensure readability in any condition, select indicators feature a Neobrite coating and the dial is equipped with a Super Illuminator backlight. The brand's signature appears at 12 o'clock.

Functions

Bluetooth® Smart
The watch is equipped with energy-efficient Bluetooth® technology, enabling data exchange with a single button press. Bluetooth® wirelessly connects the watch to a smartphone, unlocking a wide range of highly convenient features.

Smartphone time
When the watch is paired with a smartphone, the time is set automatically and always displays the current time anywhere in the world.

Super Illuminator
A single button press illuminates the dial in vibrant, on-trend colors.

Solar power
Solar cells provide an autonomous, eco-friendly energy source. Any surplus solar energy is stored in a rechargeable battery.

Neobrite Coating
The hands and/or indexes feature a fluorescent coating that continues to glow in the dark after the watch has been exposed to a light source.

World Time Function
The world time function displays the time across 29 time zones and major cities around the world.

Stopwatch 1/100 s - 24 Hours
Measures elapsed time to 1/100th of a second accuracy for a maximum duration of 24 hours. An audible signal confirms the start and stop of the stopwatch.

Countdown Timers - 1/1 sec - 1 Hour
For precision lovers: countdown timers alert you to important or recurring events with an audible signal at the set date and time. Time can be programmed in seconds, up to 1 hour in advance - especially handy for daily medication reminders or repeated training sessions.

5 Daily Alarms
An audible alarm reminds you of your daily commitments at the programmed time. This model features five independent alarms for maximum flexibility when it comes to your important appointments.

Hand shift function
This function moves the hands out of the way when they obstruct the visibility of the time, date, or stopwatch function.

Find my phone function
Lost your smartphone? Simply press one of the watch buttons and your smartphone will emit an alarm.

Day of the Week Display in Multiple Languages
The day can be displayed in your choice of several languages.

Button Beep On/Off
The button beep can be turned off using the mode button. Once disabled, there is no beep when switching between functions. However, any programmed alarms or countdown timers remain active after the button beep is turned off.

Automatic Calendar
Once programmed, the automatic calendar always displays the correct date.

12/24-Hour Time Format
You can display the time in 12-hour or 24-hour format.

Battery Level Indicator
Displays the current battery level.

The Movement

A solar quartz movement powers this watch. Reliable and precise, this mechanism ensures the hands run smoothly and all functions display correctly.

The Strap

Built for water sports and designed for comfort, this black resin strap is as stylish as it is functional. Its clean lines are carefully finished to match the watch's sophisticated look, and it fastens easily with a pin buckle.

Water Resistance

With water resistance of 20 atmospheres - equivalent to 200 meters - this model confidently earns the title of dive watch. Our watch experts agree: it handles showers, baths, vigorous swim sessions, freediving, and recreational scuba diving with ease. However, it is not intended for extreme deep-sea diving, where pressure would overcome its water resistance. For professional divers tackling serious depth challenges, we recommend models rated at 30 ATM or above. We also advise against operating the push buttons or crown while submerged, to maintain a perfect seal.