G-SHOCK GA-2100GB-1AER

The Casio G-SHOCK GA-2100GB-1A is the gold-faced entry in the “Gold and Silver Colour” pairing within the GA-2100 family — a more dressed-up take on the now-iconic CasiOak silhouette. Released alongside the silver-faced GA-2100SB-1A, this watch keeps the standard GA-2100 octagonal silhouette and Carbon Core Guard internals but treats the dial and case in a way that pushes the platform from minimalist tool watch toward something closer to a statement piece. The base GA-2100 was launched in 2019 — Casio’s official line is that the design draws on the very first G-SHOCK, the 1983 DW-5000C, which itself had an eight-sided bezel — and the GA-2100GB-1A is one of the more elegant variations the line has produced.

The case dimensions stay true to the platform: 48.5 mm lug-to-lug, 45.4 mm wide and just 11.8 mm thick, with a weight of 51 grams. That low profile is possible because of Casio’s Carbon Core Guard structure — the case is moulded from a fine resin reinforced with carbon fibre, rigid enough to function as a structural element rather than just a cosmetic shell. The two-layer back cover adds another layer of impact resistance, and the shock-proof button structure means the buttons sit cleanly along the case sides without external guards. The bezel and band of the -1A version are finished in a glossy black with a lacquer-like sheen, which is the choice that pulls the whole composition together: it grounds the gold dial in something restrained and lets the face do the work.

That dial is the defining detail. The face is finished first with a fine circular hairline treatment that catches light in concentric rings as the watch moves, and then with a vapor-deposited gold coating that gives it a uniformly glittering finish across the surface. The applied indices are treated in the same gold tone for visual consistency, the small day sub-dial sits at 9 o’clock, and the small digital LCD in the lower right quadrant reads dark on a light background. The hour and minute hands carry a Neobrite phosphorescent treatment so the watch stays legible after dark, and the hand shift feature moves them clear of the digital display when needed so the small LCD stays readable. A double LED Super Illuminator lights both the analog face and the digital display.

Inside is Casio’s module 5611 — Japan-made — driving the standard GA-2100 feature set: a 1/100-second stopwatch with a 24-hour capacity (elapsed, split, 1st–2nd place modes), countdown timer up to 24 hours, five daily alarms with hourly time signal, full auto-calendar to 2099, world time across 31 time zones (48 cities + UTC) with daylight saving on/off, 12/24-hour switching, and a button operation tone on/off function. Battery life is approximately three years on twin SR726W cells. Construction is shock-resistant; water resistance is 200 m. The GA-2100GB-1A is, in short, a more grown-up version of the CasiOak — same slim, well-proportioned platform, but finished with the kind of detail that lets it sit comfortably alongside dressier watches without giving up any of the toughness underneath.

Basic Information

Reference: GA-2100GB-1A
Collection: G-SHOCK — 2100 Series (“CasiOak”), Gold and Silver Colour line
Case size (L × W × H): 48.5 × 45.4 × 11.8 mm
Weight: 51 g
Case and bezel material: Carbon-fibre-reinforced resin (Carbon Core Guard structure), glossy black finish
Band: Glossy black resin
Construction: Shock-resistant; Carbon Core Guard; two-layer back cover
Water resistance: 20 bar (200 m)
Power supply and battery life: Approx. 3 years on SR726W × 2

Exterior

Glass: Mineral Glass
Dial: Three-dimensional layered face with circular hairline finish; gold-colour vapor deposition across the dial and on the index marks
Hands: Neobrite phosphorescent treatment on hour and minute hands

Watch Features

World time: 31 time zones (48 cities + UTC), daylight saving on/off
Stopwatch: 1/100-second; measuring capacity 23:59’59 (24 hours); modes: elapsed time, split time, 1st–2nd place times
Countdown timer: Up to 24 hours (1-second increments)
Alarms: 5 daily alarms; hourly time signal
Calendar: Full auto-calendar (pre-programmed to 2099)
LED light: Super Illuminator — high-brightness double LED (LED for face and digital display); afterglow
Other: Hand shift feature (hands move clear of the digital display); button operation tone on/off; 12/24-hour format
Accuracy: ±15 seconds per month
Regular timekeeping: Analog (3 hands: hour, minute, second) + digital; day sub-dial; date display
Module: 5611