Casio G-SHOCK G-Steel GST-B400BB-1AER Watch
- Movement: Tough Solar power technology converts light into energy, eliminating battery changes.
- Water Resistance: 20 ATM (200m) rating suitable for professional diving and high-impact water sports.
- Durability: Carbon Core Guard structure provides superior shock resistance in a slim profile.
- Connectivity: Bluetooth integration allows for seamless smartphone synchronization and automatic time adjustment.
- Design: Minimalist all-black aesthetic featuring a premium resin strap and mineral glass dial.
- Functions: Integrated chronograph, dual time, and multiple daily alarms for precision scheduling.
- Dimensions: Compact 46.6mm x 42.5mm case diameter with a 12.9mm thickness for ergonomic wear.
- Weight: Lightweight 80-gram construction ensures long-term comfort for daily use.
Casio G-SHOCK G-Steel GST-B400BB-1AER Performance Overview
The Casio G-SHOCK G-Steel GST-B400BB-1AER is a high-performance analog-digital timepiece engineered for modern professionals demanding a durable tactical watch. This model combines a sleek, monochromatic black aesthetic with advanced solar-powered functionality, making it an ideal choice for reliable everyday carry watches. By integrating Bluetooth connectivity, it provides precise timekeeping and world-time capabilities across multiple zones, ensuring maximum utility in a rugged, stylish package.
Technical Specifications and Solar Movement Efficiency
This timepiece operates on a proprietary Tough Solar movement that ensures indefinite power reserve through ambient light exposure. The watch utilizes a high-clarity mineral crystal to protect the black dial against scratches while maintaining visibility in varying conditions. Users often inquire about how to set dual time on G-Steel watches, a process streamlined through the G-SHOCK Connected app, which calibrates the internal movement for peak accuracy within ±15 seconds per month.
Durability and Lifestyle Ergonomics
Constructed with a Carbon Core Guard, the case offers extreme structural integrity while maintaining a slim profile, solving common concerns regarding heavy-duty watches for small wrists. The 20 ATM water resistance rating allows for deep-water immersion, making it one of the most versatile waterproof watches for swimming on the market today. The high-grade resin strap provides a secure, hypoallergenic fit, ensuring the watch remains comfortable during extended wear in active environments.
What is VAT?
VAT is a TAX that is applied in all European Union (further EU) countries. When selling internationally there are different VAT rules depending on whether the subject is buying or selling goods or services within or outside the EU. These rules also apply to businesses selling online. WatchExclusive owned by I&M Montres Pvt. Ltd. belongs to this category of business.
VAT-free shopping (0% rate)
VAT does NOT apply for orders shipped to countries outside the European Union (EU) and to NON-EU member countries.
- WatchExclusive uses geolocation software that will determine the customers country's IP address and enable or disable tax-free shopping according to the terms mentioned above.
- If conditions are met, tax-free products prices will be automatically applied and shown. This will be indicated in the Shopping cart and Checkout as "Included Tax Value: 0.00." (see screenshot below).
- If a customer uses VPN services or software to hide the IP address, they must register a new account, with a billing address which fulfills the country requirements mentioned above. Tax-free prices will be displayed after successful registration.

Import duties and local taxes
- Orders shipped outside the EU may be subject to import duties and local taxes which are levied once the package reaches the destination country. Any additional charges for customs clearance must be borne by the customer.
- WatchExclusive will provide all necessary documents such as an invoice, customs export declaration, shipping documents and tracking number, to ensure a fast and successful customs clearance.
- Customs policies vary widely from country to country. Therefore, it is recommended for the customer to contact the local customs office for further information.
VAT-free shopping within the EU (B2B)
- VAT is applicable to all orders shipped within the European Union (EU) and will be charged at the rate of 20%.
- EU VAT registered companies may choose to remove the VAT by providing us with their VAT registration number at checkout. (This does not apply to Slovak VAT registered businesses where VAT must be charged.)
EU countries: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden.