Casio G-Shock G-Steel GST-B100-1A 'Carbon Core' Chronograph
Tool Watch / Chronograph / Connected Smart Watch · Casio (Casio Computer Co., Ltd.). G-Steel is a premium sub-brand of G-Shock aimed at professionals.
Period: Modern Luxury/Rugged (2017-present). Part of G-Shock's movement into 'metal-clad' designs to bridge the gap between digital tool watches and high-end analog luxury.
Type
Tool Watch / Chronograph / Connected Smart Watch
Brand
Casio (Casio Computer Co., Ltd.). G-Steel is a premium sub-brand of G-Shock aimed at professionals.
Movement
Tough Solar (Light powered) with Bluetooth Mobile Link. Caliber 5513. Features dual-coil motors for rapid hand movement and approximately 5 months power reserve on full charge without further light exposure.
Dimensions
Case Diameter: 53.8mm; Thickness: 14.1mm; Lug-to-Lug: 58.1mm; Lug Width: Proprietary integrated lugs.
Description
The GST-B100 is a bold, analog-only G-Shock that emphasizes mechanical aesthetics through its rotating 'turbine' subdial. It combines the legendary shock resistance of the G-Shock line with a refined steel exterior suitable for business-casual environments. Its presence is massive yet engineered for comfort.
Key Features
The 'Turbine' subdial at 9 o'clock which rotates to indicate alarm status or battery level, and the Bluetooth smartphone link for automatic time synchronization.
Dial Description
Multi-dimensional black dial with turbine-inspired 'Propeller' subdial at 9 o'clock. Includes oversized applied 12 and 6 numerals, neo-brite luminous baton indices, and a date window at 4:30.
Case Material
Stainless Steel and Resin 'Layer Guard' construction. Features a mix of brushed top surfaces and polished chamfers with a black resin inner core.
Crystal Type
Flat Mineral Glass with high scratch resistance, slightly recessed below the bezel line for protection.
Bezel Details
Fixed stainless steel bezel with ten screws and etched 05-60 minute scale markings. Features a brushed circular finish.
Crown & Pushers
Large screw-lock crown at 3 o'clock; four oversized knurled 'piston Style' pushers for chronograph, light, and Bluetooth pairing functions.
Bracelet or Strap
Heavy-duty black resin strap with a stainless steel tang buckle and wide metal keeper.
Caseback Details
Solid stainless steel screw-back with 'G-Steel' and 'Triple G Resist' engravings, model number, and module identity.
Movement Type
Tough Solar (Light powered) with Bluetooth Mobile Link. Caliber 5513. Features dual-coil motors for rapid hand movement and approximately 5 months power reserve on full charge without further light exposure.
Water Resistance
200 Meters (20 Bar). Suitable for recreational diving, swimming, and high-impact water sports.
Origin & Provenance
Japanese Movement / Cased in Thailand or China. It uses Casio's in-house solar-atomic technology.
Age Estimate
Circa 2017-2021. This specific design language debuted in 2017.
Cultural Significance
Represents the 'Adult G-Shock' movement, transitioning the brand from plastic teenage accessories to respected metal timepieces for enthusiasts.
Condition Notes
The image shows a watch in 'Good' used condition; minor scuffs on the steel bezel are visible, which is common for this high-polish/brush combo. Lume appears functional.
Value Estimate
MSRP: $320 - $350. Secondary Market: $180 - $250 depending on condition and inclusion of the original 'hex tin' box.
Care & Maintenance
Recharge by exposing to sunlight regularly. Every 5-7 years, the rechargeable CTL1616 battery may need replacement. Gaskets should be pressure tested if used for swimming.
Similar Watches
Casio G-Shock MTG-B1000 (Higher-end, sapphire crystal), Seiko Astron (GPS solar alternative), Citizen Promaster Skyhawk.
Interesting Facts
The 'Turbine' subdial was inspired by the blades of a jet engine. This was one of the first G-Steel models to drastically reduce case thickness compared to previous generations.